but a centralized service, ACINQ, controls the opening and closing of "your" channels, you will likely route through their node for most payments (for a fee).
It's good enough for now
At least take can't steal your funds
"probably won't steal" is more accurate.
you *will* have a channel open with the ACINQ node. is your Phoenix node always online? are you using a watchtower? your own or from a service?
i am not saying ACINQ is going to steal channel balances. they are incentivized to support their customers.
using Phoenix is entering into a banking business partnership with ACINQ. they are making decisions about how to handle your payments, and you are paying them to do so.
Can't steal as they don't hold the private keys
i urge you to research what an LN payment channel is.
funds on LN don't sit "in a wallet." you do not have that sort of passive security.