Is using an aggregator for cross-chain swaps always better than just using a single CEX? Or does it depend?

I sometimes just use Binance for cross-chain swaps because the rates seem decent and I trust the execution. But I know there is probably a better way.

Is an aggregator like RocketX that uses both CEX and DEX routing genuinely better than going directly to Binance for cross-chain swaps? Or does it depend on the pair?

Also the non-custodial pitch sounds appealing but I want to understand the actual tradeoffs. If RocketX routes through Binance's order book, what is the practical difference from just using Binance directly — other than not needing an account?