There is still trust inherent Bitcoin's math. For example that your wallet can't be drained by a faulty signature construction. Or a qauntum computer.
But yes, I take your point there is a wider surface in Monero's case. I agree with that point.
I weigh the UX of being able to easily spend without sharing my balance very highly.
It's a tradeoff I think is very well worth it in justifying both using and holding Monero. There's nothing wrong with holding both.
