You sorta make a good point but why is that when my Emboar takes on a Salamence, that's right a Salamence it can take it down with one hit and manage to knock out a Hippowden as well in a row holding just a sitrus berry. If you were to have a battle without super effective moves Emboar can be decent in some way. It's to do with how you use it. GOSH!
OHKOing Salamence isn't exactly a notable accomplishment; Salamence isn't some super bulky tank. A LO Vanilluxe can OHKO offensive Salamence 3 times over with one Ice Beam, not to mention that most Salamence sets will easily outspeed and OHKO an offensive Emboar anyways. And I'd like to see these Emboar and Hippowdon sets you're talking about. Even a 252+ Emboar's Grass Knot caps out at 86.66% against a physically defensive Hippowdon, and that's pretty much Sitrus Berry Emboar's best shot at OHKOing it. A OHKO is only possible against a Hippowdon that is barely investing in bulk at all, which is a terrible idea, and beating bad players with bad EV spreads proves nothing.