With drivechains, Bitcoin users can't opt out. That's the difference. Drivechains are soft forked into the consensus by miners.
That may be one of the reasons some people are wary of them. Maybe they don't want to use drivechains since there is no way for them to opt out of it. One of the purported benefits of drivechains are for altcoins to be implemented on them, but with hundreds of alts already, I think it's too late to attempt to clean up that mess. Regarding
BTC maintains hashrate security in the long run.
what is this supposed to mean? Bitcoin already has a high hashrate without any other layers which reflects its mining difficulty, so it's pretty much impossible for anyone to manipulate the blockchain nowadays, compared to say 10 years ago. I'm not sure what drivechain is trying to solve here, unless it's trying to solve its own hashrate problem, which bitcoin is free from having.