Context matters and you seem to want a one size fits all answer. I don't live on a planet where that works.
Practice wheel landings aside, there are not all that many circumstances where I find a wheel landing to be necessary in the real world. Living here along the east coast, I see even less need for a wheel landing than I did living out west. I learned to fly in western South Dakota where the average wind velocity is 20-25 mph depending where you are. That's "average". Flying in higher winds, and in particular in winds with higher than average peak gusts is common. In addition, the winds are often not just gusty but also variable over a 30 or so degree arc.
That combination of very gusty and variable winds can create a situation where a wheel landing is useful to ensure the aircraft doesn't come off the ground after you've touched down if you encounter a 10-15 kt gust and/or give you a bit more control. In that specific real world case you are also going to increase your final approach speed by half the gust factor, which will mean a slightly higher approach speed in a real world situation where a wheel landing makes more sense than a full stall landing.
*IF* you opted to make a full stall landing in wind conditions that included a significant gust factor you'd also increase your approach speed accordingly, and unless you were an idiot, you'd also flare and bleed of the excess airspeed just inches over the runway so that if the wind shears you'll settle onto the runway gently, rather than drop onto it from 2-3 ft in the air. Practically speaking if I settle onto the runway due to wind shear during an intended full stall landing, I'll release the back pressure and convert that intended full stall landing into a tail wheel low wheel landing and then move the stick forward to keep the tail off, in order to prevent the aircraft from becoming airborne again if the wind gusts again. The point here is that the approach speed for each type of landing is based on the wind, not the intention of a 2 versus 3 point landing. But in the real world, if you need a wheel landing, it'll be in wind conditions with a gust factor that warrants a higher airspeed.
The general concept is that you should not be selecting an approach speed that is faster for a wheel landing than you would for a full stall landing, just because it is a wheel landing. The general idea is also that there are only a few specific situations where a wheel landing makes more sense than a full stall landing.
The caveat/problem is that many students learn wheel landings starting with a higher than normal airspeed and some additional power in order to flatten the glide angle and give them more time to "feel" for the runway. By extension, having a student fly nearly the entire length of a 7000 ft runway 6" off the runway at 60 mph or so can be a useful method to help develop that feel. However, once they've developed a solid understanding of the visuals and can quickly find the correct height and precisely arrest the descent rate to put the wheels smoothly on the runway, the need for that long, flat portion of the wheel landing dissipates. Yet students continue to do what they were taught and continue to make wheel landings at faster than necessary airspeeds, just because they are making a wheel landing.
We're on the same page with this caveat, given your comment that you teach with power initially and then fade to power off wheel landings (where the pilot is using the energy of the aircraft to arrest the descent).
----
I have heard that the DC-3 and the Beech 18 should be considered to be wheel landing only aircraft. I've also heard pilots comment that the Globe Swift can be inconsistent in a full stall landing and that wheel landings are a better default choice for a Swift. However, since learning to fly in 1982 (and in several years hanging out as the airport kid prior to that) I have never heard any pilot say, until today, that a Decathlon or Super Decathlon cannot be landed three point.
The stall speed of a Decathlon is literally 2 kts faster than a Citabria, the weights are very close, the Decathlon gear is just as strong, and the Decathlon airframe is stronger. With the exception of the 7GCBC, the CItabria also lacks flaps like the Decathlon.
To be fair, the Decathlons shorter wing and less lift efficient airfoil, will produce a bit steeper descent angle, so you'll want to carry a bit more speed into the flare (70 mph, rather than the 65 mph you'd use in a Citabria) and depending on weight you may want to leave a little power on (900 rpm -1200 rpm) to control the descent rate/angle, but a full stall landing is totally permissible and is in fact normal.
I'm sorry but weighing all the evidence, including the POH for the Decathlon, I have to put your comment in the "Unmitigated BS" category. I have no idea why you think that's the case but I am really interested to hear your explanation.