>>718985167
>accident turned into a feature
This isn't necessarily a bad thing. I don't think dev intentions matter as much as how players can harness or utilise a particular exploit or movement technique to their advantage. Combos in Street Fighter and wavedashing in Smash Melee were both accidents borne out of engine quirks, but both became practically ubiquitous within their respective genres. TF|2 also has its fair share of movement exploits that the devs likely didn't anticipate, like tapstrafing. Sure it'd be ideal if the devs recognised and fleshed these exploits out, but I think their recognition and popularisation amongst players already solidify them as "legitimate" features.
>>718985327
>500x easier to aim
Not if you're on PC where there's no aim assist. There are a fair share of projectile weapons, too. The sniper in the webm, for example, isn't hitscan.
>Why would I play this?
I think it's fun, and my very first FPS games were Quake 3 and Xonotic on my older brother's PC. Give it a go and try learning the movement, and maybe it'll click for you.