Oh lol
And OHKO moves can be described as the meta, in previous Gens HO was so common and No Guard Deo-S were on almost every HO team and even on a few Balance, they finish games so quick, free ELO, you can say. Now, with Neutralizing Gas being everywhere, the other abilities lost their viability, and therefore you’d see many OHKO moves even on non-No Guard Pokémon, same reason, they finish games quick.
Another reason is Eternamax’s godly bulk. You either need a Cramorant or OHKO moves or serious strong hitters (Stored Power Rex) to get them, as like they survive almost *everything*. Eternamax is the meta ofc, and to end them, you need OHKO moves.
Plus it gives you a fairly nice advantage if you hit a few early-game.