I have tons of smart sockets (https://www.amazon.de/dp/B077VNL75Z - but I got them for a little more than 10€ each)
They are great. Everytime I listen to music / use Apple TV it switches on my Yamaha HS7 (so lots of switching over the day) - working good so far. You could build some kind of cascade / delay with them (e.g. with a Raspberry and Home Assistant). And I bet they already paid for themselves.
The “brain” of my setup. 
Technically not “switching on”, but at the moment the first thing I do before I start making music is get a fire going.
MC-707, just because it’s the rightmost outlet.
My wife
Yes its safe.
Depending on the quality of your fusebox / thickness of cables in walls, I’d say. My flat almost burned once (I also only have 10A fuses). So it might not be harmful for the gear … but might be overpowering your powerlines. I’m not an electrician though 
But better safe than sorry 
I’d switch Speakers with Gear, since some gear (i.e. DSI Tempest) is sending a loud pulse on turning ON/OFF.
This is the so called “soft switch”.
I have everything setup on a raised table and it’s geared for performance. It all gets powered on. Though, monitors on last. Monitors off first.
Waa Waa Weee
The first thing I turn off is my home office light, it’s the closest thing I get to “leaving the office”. Then it’s a toss-up for whatever is calling my name. Lately, it’s a beer and the OT!
I always wonder if it does any harm to my Machines if I switch off/on everything by the switch of the power cord? Like giving them not the time for booting down correctly. Speaking of OT, Prophet 12, Pro3.
So I should first read all the entries here. Hahaha.
I am not the only person thinking of it
Ah ok, I should have been more precise.
I have two long extra shielded power distributors.
Brennenstuhl Premium-Line Steckdosenleiste 6-fach mit Überspannungsschutz bis zu 26.000 A (Steckerleiste mit 1,8m Kabel und mit Schalter, Made in Germany) schwarz https://www.amazon.de/dp/B099WKS8ZB/ref=cm_sw_r_cp_api_glt_i_FKMF1NR1MRYVX83Y5ERY?_encoding=UTF8&psc=1
The monitors and the RME is connected to this, and will be switched on, when I switch the distributors on. Computer is separate powered. Any synth I want to currently use is connected as well, but won’t get switched on by the distributor, as long as it has its own powerswitch. Plus the apartment building around the home studio is from 2016, so no problems with electricity so far. My former apartment was from the 1950ies…always problems.
xone 96
Ah no, synths that have their own power switch I switch separate. In case of the Hydrasynth Desktop it is a challenge though. What were they thinking? 
Almost always my Orange Thunderverb 50’s power switch, so it has ample time to warm up while my computer starts up too. Gotta get those tubes ready for that juicy guitar tone.
