It's still a single point of failure.
So now if you lose your phone you also lose your wallet and are really screwed. It’s better to hedge your risk and keep important stufd in different places. It might increase the chance of losing something but mitigates the risk of losing everything. I think most people would prefer to mitigate the big risk instead of the small ones.
not a single point at all, it's just a couple cards in the slot.