I hear this argument in a lot of forms and I don't buy it. Whether we're talking about lighting consoles, mixers, followspots, movers, or whatever, I don't think one should ever buy equipment that's less suitable for the circumstance just so students can learn how to use it.
No matter how hard you try, you can't protect your pupils from running into tech they don't know in the future. This is why instruction manuals exist. Isn't it just as important to teach them to go with the best equipment choice they can?
If you go with the
source four solution, then you'll have students that will say: "Why don't we have a real
followspot? What's up with this stupid thing?" This gives you the opportunity to explain that this solution saved you money, space, and time, and keeps the variety of lamps in your inventory down. Now you have a student that can not only run a followspot, but understands a little more about the logistics of the craft. And in a field where money is anything but abundant, there can't be anything wrong with that.