I like systems, to the extent that they support the story and the players and encourage RP. I like the element of random chance that dice bring, I like that +sheets force people to pick what their character is good at and what they’re not good at. To me RP is improv and the system/dice is one of several things giving you new prompts to improv with. I like that.
My forays into MUCK RP and Discord RP where there were no systems were not satisfying to me. A little bit of “you can’t fight this character because it is IC for me that I never lose so you will die,” lots of “I got you” “nuh uh, no you didn’t” like kids playing, and lots and lots of characters who are the best psycho killer in the entire universe at every single weapon that there is AND the best at persuasion and social skills AND the best pilot AND the best mechanic AND the best doctor, etc. I think that stays on the rails a little more with a +sheet/dice.
Many of my friends have long experience with freeform games wherein the players all seem to have been pretty mature and did accept losses/failures, did pick a lane for their skills, etc. I just personally don’t have that experience, so “at least some mechanical systems” is my personal preference.