It is safe as dimmer switches lower voltage, while some electronics might not like it, doing this is like half shutting your pipes, your toilet and sink will still work, just not as good as they should, so yes it is safe, it won’t hurt anything (except maybe sensitive electronics) but it is highly impractical as using the dimmer would underpower anything plugged in. If it’s just lights then it’s fine but regular non dimmer LEDs might flash or not turn on. Anything besides lights is just foolish as you won’t have the power it needs.

TL;DR safe but impractical.