Someone in the shop bet me my little battery inflator was useless for anything beyond tire tops, so I made a proper fitting for it and it's been surprisingly handy since. The trick is a small brass adapter that threads into the hose end, a few wraps of thread seal tape, and a standard quick connect on the front so any of my air fittings click straight on. First tip: wrap the tape the same direction the threads turn, otherwise it just balls up and peels off when you screw it in. Second, keep the connection snug but don't gorilla it, plastic housings crack easier than you think. Third, know the limits. These little pumps are made for topping tires and balls, not for running a nail gun all afternoon. Anything that needs steady airflow will cook the motor or flatten your battery in minutes.
Where it actualy shines is small jobs. Filling a wheelbarrow tire, blowing dust out of a sander, seating a stubborn bead with a quick burst, airing up the kids' bikes without dragging the big compressor out of the shed. I keep the inflator and one battery charged in a drawer now and the compressor mostly stays put. Worth twenty minutes and a couple of fittings to set up, honestly.