I would answer (for the benefits, not for the technical part) that if your don't use your own node, you are using the node of someone else. It means less privacy, it also means less sovereignty as you rely on someone to be able to broadcast your tx. Finally it also means less decentralization for the Bitcoin Ledger and the more it is (decentralized, resilient, censorship resistant), the more your stack is valuable.

Privacy, sovereignty, with a touch of (not so disinterested) altruism