Matchmaking is ABSOLUTELY necessary on casual. When games are too difficult for new people to learn because they keep getting tanked by veterans looking for easy kills, EA and Respawn very quickly lose new customers. It's why I never played League. When it first came out, I couldn't figure out what the hell I was doing before getting slaughtered left and right and being called names by teammates. If I can't learn it, I won't know it.
The devs ARE responsible. And they've found through extensive testing that the matchmaking system actually leads to a greater player-base gain and a better experience for newer people. For me, I'm new to FPS's in general. When I started, I didn't know what "ADS' was and was used to simple "shoot 'em up" games. The most difficult being the Borderlands franchises. That said, I had a LOT to learn when I came to Apex. Hell, I still do. BUT without the Matchmaking, I'd get frustrated with getting merc'd left and right and find another game that lets you develop your skills.
There are lobbies I land hot, get wiped. But there are other lobbies where I can easily make it to Top 3 without breaking sweat. That variety allows me to become slightly better with every game, and learn from my decisions in-game.
Yeah you get Smurfs in low-rank casuals. But most of the games are pretty evenly matched with my skillset to push me up. I'll admit, I have a Smurf account. But that only to play with some friends who are waaaaaaay more casual about the game than I am, and getting them into lobbies they can handle. I'm nowhere near the skill to carry a team in the lobbies my level generates, so that's the purpose my Smurf account serves.
In all fairness, my stats aren't all that much different; so it's not giving ME a competitive advantage, but it does make it to where my level 40 friend doesn't get overwhelmed when coming into my lobbies when I'm nearly level 400.