It does change the security assumptions. Currently reorgs do not help miners, ever, at all. They are rare and an unfortunate result of the decentralization. If you add those shitcoin chains where value is being passed around in sidechains then you can potentially incentivize miners to intentionally reorg the base layer. That would be very bad.

But again I really suggest you study more and talk less because you do not know enough about what you're discussing to have such strong opinions, both of covenants and drivechains.