I agree with you that there is no risk to turning off a PC or it's peripherals from a power strip.
However, the electrical grid where I live has brownouts on a daily basis lasting a few seconds. I have UPSs on everything because I don't wish to lose active DVR recordings, open documents on my PC, or get killed in an online game because the power browned out for 2 seconds.
If you have power brownout issues in your area (common in Florida -- even on a sunny day), a UPS on home equipment is perfectly reasonable.