In my experience, I have only used the single unit economy strategically in blitz mode to avoid wasting time in battle by skipping their turn. And in setups like 1 wolf + a stack of wolves. But in 90+% of battles involving single units, 7 stacks are used.
Advanced alt is also a somewhat confusing feature. In blitz mode, it is more likely to lead to confusion than to speed up the process.
However, shift is useful, and it's strange that they didn't come up with it in TE. It's a logical and useful function to divide a stack in half. I would like to see it added to TE mode.