The tradeoff is that Drivechain requires a soft fork. It is tiny change to Bitcoin Core and only affects those who 'opt in' into BIP300/BIP301.
The benefits are potentially limitless as mainchain/L1 bitcoin remains secure and decentralised where sidechains/L2 bitcoin can have any functionality the user wishes while providing revenue to miners via sidechain/L2 transaction fees.
Sorry but you can't get away with such a poor argument. The soft fork is not the tradeoff. The unknowable miner incentives is the tradeoff. UNKNOWABLE. Therefore, no thanks.
The worst case scenarios is that all the users of a sidechain are at risk of their BTC being stolen by miners. So the risk of theft is 'opt in' for the user of a sidechain.
Drivechain allows miners to collect significantly more revenues (or more).
In return, they are encouraged to (but never required to):
…activate/deactivate sidechains, in order to maximize BTC’s price & maximize total txn fees.
…investigate the status of a disputed withdrawal (of which there can only be one per 3 months).
This is precisely what Satoshi intended for miners. Merged mining was invented by Satoshi, and has been in continuous use ever since e.g. Namecoin and Rootstock.
