Although it is rare for me to make a yeast based pizza dough these days, I have not been as certain that combining the two is not helpful, etc.
I do not necessarily look at it as an SD dough requiring help from yeast. More the other way around. I think of it as a yeast dough, that gets help from the SD starter. Not help in the form of more lift, but help in the form of more flavor.
I guess the analogy is a poolish based pizza dough. Using a poolish has little, if anything, to do with more or less lift. I think it is much more about adding flavor + other structural items that I know I do not understand.
So, rather than making a yeast dough with a yeast based poolish, it is more about making a yeast based dough with an SD based preferment. Nothing to do with lift really. The dough (don't get mad Craig) can be cold fermented, etc.
It has been quite a long time, but my Varasano type doughs (cold fermented with 0.25% IDY for 3 days) have a combination of SD starter (about 9%) and yeast. If I recall correctly, I found the flavor superior to the flavor of just a yeast based dough.
So, I think of it (a combination of IDY and SD) as a potential enhancement to a yeast based dough, not a not a crutch for an SD based dough.
Hope that makes sense.