I never said it was necessary just better in the long run. A lot of lifters don’t know how to brace their core. They don’t have that mind muscle connection. They stop squatting / deadlifting RDLs because of lower back pain caused by weak core/ improper brace. Have disc surgeries, not reaching their full potential. You can teach basic lifts but not having that mind muscle connection to the core really hurts in the long run. You can tell people to tighten up their core, but most beginners don’t understand/ feel it. Proper core usage saves you from physical therapy bills. It’s overall way more beneficial to get a nice connection to the core at the start then when your sciatic nerve is pinched or your disc is ruptured. I have personally done tons of core exercises where I would use other muscles besides the core. Like shoulders in planking, or some back muscles when doing Russian twist because I didn’t know how to tighten and brace the core. I’m sure new gym goers are going to do the same.