Running a full bitcoin node is NOT really necessary. You can easily and safely connect to a friend node and is perfectly fine.

But unfortunately nowadays many people use this "run your own node!" as a virtue signaling that do not serve for nothing.

Just because Bitcoin is decentralized it doesn't mean we should eliminate any trust. See for example the guide I wrote about running private LN banks for family and friends, local communities: https://darth-coin.github.io/merchants/private-banks-over-ln-en.html

Such scenarios could make bitcoin adoption to explode, not dumb apps the hide everything from user in a fancy UX.