Honestly I don´t use it a lot, and I don´t even remember doing it even back in ETQW were you actually had to use appropriate classes for objectives and stuff. At least for pub, and in comp it was quiet rare to do - so don´t feat of 24/7 selfkills pixel 
So since this isn´t the matter anymore, and there is almost never a need of a specific merc (who needs class objectives or medics or anything else in the team really…) I use it even less tho. I only use the self kill when I am bored of the current merc I am playing and don´t want to wait until I die…
The use of suicide will get little bit more significant (depending on proficiency, maps, etc.) in competitive. It is a major factor for the tug of war you experience, since it allows you to adjust your defense/offense quicker, making an objective to something you possibly fight for couple of pushes. So besides just looking at the timer, there is a lot of strategy and quick thinking behind it. Obviously that´s nothing that is easy to understand or even see while watching (without explanation that is). And anyone who is saying that it is dumb/easy just makes it even more obvious that there is something more to it what you will just be able to understand and utilize after playing the game for longer time and in a competitive environment.
I honestly don´t think that this “feature” is well rounded, but for sure it is at least something that gives the game something to play around besides the obvious shooting (+spam). Changing the re spawn up would make this totally useless unless the game undergoes many changes that aren´t likely to happen (like everyone can pick every merc that has being drafted by your team). It actually also makes sens, to kill yourself with a knife, in order to not give away valuable information. So lore wise it absolutely makes sens and is easy to understand (unless you don´t want to) while toggling self kill timers and self kill restrictions are far more unreal.
So regardless of how we like it or not (its not my favorite either, I allways sucked at that :D) it is for sure a mechanic that
doesn´t really hurt anyone (you don´t have to use it, and when you don´t understand it you probably won´t even notice it), evolves heavily around teamplay and decision making and is a very distinctive skill that can result in a huge face palm, game changing moments and even heroic moves. All components that mostly have been taken out of the game already for the sake of basically nothing and I hope that it stops now.