ecash is a banking technology. This means you trust the mint not to rug you just like you trust Coinbase not to rug you.

That said, the technology is super private so targeting individual customers is impossible, they won't even know your balance, your name, or anything really.

Using lightning is using bitcoin directly. For now it's the better option but can become expensive if you need to constantly manage your liquidity (a technical task we need to do sometimes to maintain our lightning wallets); especially when on chain fees are high.

Ecash also is faster and can more easily integrate with web servers and some unique user cases that using lightning for might be clunky.

For typical use day to day, I'd recommend sticking to a lightning wallet. If you like to tinker, play with the ecash stuff. If Lightning wallets are too complicated for you, maybe ecash can help, but it comes with the trade-off that your funds are at risk of loss because they are backed by bitcoin held by a custodian.