I use 10s on short scale Strat necks. 9.5s on standard scale Strats.
If you play with distortion, thick strings might not make much of a difference. but I definitely hear a difference playing clean and there is definitely a volume difference between 8s or 9s and a 10 pack.
That Beato video.....guess what.....they never play CLEANLY. Compare an .008 and a .010 using single coils with a totally clean tone. The difference in volume and tone is clear.