Why PBM:
Carrying a bunch of balls around got old.
The contraptions on the market today....
Most ball hoppers are designed for large volume and training <coor>; “low volume”.
Most tennis is casual where players are meeting up with other players to just hits some balls around, “casual tennis”.
PBM - personal ball management
Easy to carry, see quality of and switch out balls when time, and easily retrieve without straining back.