Now you have to carry dozens of dongles, but the objective is long-term. I almost never need VGA/DisplayPort/etc for instance because it was standardized to HDMI (and now to USB-C). What port does that non-bluetooth mouse use? USB, right? Well before you'd have to check, because it could be using a PS2 as the keyboard. But now you know for sure they use USB if they use any port, which is a good thing. I remember my older cousin complaining about me having a USB mouse when I should have a PS/2 back in the day.
Forgot your phone/laptop charger? You can borrow mine as it will be the same USB-C. Yes, now it's painful, but in ~10 years it will be glorious. However, the problems of the switch are happening now while the benefits will come unannounced, which is a pity.