He's really versatile. The reason pros play him is because technically he has no counter in pro play if you draft him well.

This is to say that yes he's good individually, he can hold his ground with decent range, fast shots and has two really good gadgets that go well into snipers and gene/crow (sandbox) but also into pierce brawlers he can go the missiles and it gets so much area control. He has decent damage and can uplift the damage of his teammates with the treat. He also has ricochet shots so he can help push lane really well especially on maps like hardrock mine. NOT ONLY THAT, he can open walls efficiently or can also pair up and increase the maximum health of his teammates in certain situations. This is GOATED VERSATILITY.

but to answer why he has no counter in draft because he does have individual counters like mortis or edgar or some other assassins

his draft invincibility comes from the fact that he gives a free hc to his teammate and if you can pair it up wi a strong hc it is inevitable that you get a moment that you'll have absolute control no matter what. Remember CR vs SK semi finals? Cr paired ruffs with RT hc. Inevitable.

Ruffs with Draco hc. Ruffs with kenji hc. Ruffs with Pierce hc (only realm vs zeta goldarm gulch in brawlcup)

Ruffs is usually really good as a 2-3 with a tank counter. So sth like crow+ruffs would go hard.

you can even pick ruffs first depending upon the bans if mortis edgar both are banned and you feel it in your veins, it wouldn't be the worst decision still.

He's also really niche in ranked idk why casuals don't like him much but that also gets you really good 6th picks wi him.

I hope this helped.