I'm not asking for a personal opinion of pre-1.9 pvp or post-1.9 pvp. I just wanna know why 1.8.9 is better for servers than to use the latest version if it makes the attack cooldown non-existant anyway?
The cooldown, sword blocking and other changes are the only reason PVP players care about 1.8.9, it's not the performance or other benefits I think 'as' much but it could be a factor due to how much bigger Minecraft is now and how performance has changed across versions I guess.
Tipped Arrows, elytra and other benefits I think would add to the PVP experience for more weapon, navigation and other opportunities but that's just me. I know spam clicking is the way to go but for other options it just makes sense for projectiles/travel besides how servers tweak things.
Otherwise the servers shouldn't be too different I assume. I'm not a PVP person or a big server player but that's my guess at least.
Well, I just want to say 1.8.9 pvp is not good, but 1.9+ isn't any better in my opinion. I prefer to pvp in 1.8.9. If you use 1.16 to pvp in a 1.8.9, then a lot of bugs will occur. (Such as hit registration.) 1.8.9 is optimized for 1.8.9 servers.