I've been able to do really cool stuff that I would never have otherwise bothered with by having an LLM generate Overpass queries + walk me through complex setup steps with QGIS.

The flipside is that QGIS and overpass are so complicated that only with LLM assistance they're truly usable.

(Applies more to QGIS than to overpass, though both could stand to improve a lot in terms of usability)