I think there's a few things to consider:
1) Changes in form between lower percentages and higher percentages. A lift at 100% very rarely looks the same as a lift at 70% or less for most people. Something Talmant/Pavel talks about is making each rep consistent with what your heavy work looks like.
2) Losing touch with the heavy weights. Constantly training at 70% or less is tough when you get back to 100% max weights, even with a break-in period. Some heavy work needs to be maintained throughout or partials.
3) Transference between rep ranges. Getting better at 10 reps will get you better at 10 reps, will there be carryover? Is it worth it, in place of just more work at what you want to get better at?
4) Tendon/ligament strengthening.
5) Mindset of coping with the heavy weights. If Grade-A form is possible at lighter weights, but you fall apart at max then more max work is needed. Lower percent work doesn't teach you to grind either.
I'm of the opinion lower percentages are useful, I've just had varying results in my own training when transferring them to max work.