One thread from last year, where we discussed the idea in general:
Originally, in the 1920s, it was actually more common to take a few breaths in between each rep, not just after hitting failure at 10. But the method you described is more common nowadays.
Yes and no, depending on who you ask.
Randall Strossen's popular "Super Squats" routine from the '80s, and most of the earlier 20-rep squat-focused programs, recommend lower volume full-body training as part of the same workout (1-3 x 10-20, 1 exercise per bodypart). To say the program is challenging is putting it lightly, but that's half the point.