My guess: In tabletop, when you perform a short rest, you can choose to use hit dices to recover hit points. You can use as many hit dices as you have levels. Once you no longer have hit dices to recover hit points, you have to do a long rest to recover them. In game, when you do a short rest, they automatically spend hit dices so your characters can recover hit points. My guess is you'll have as many short rests as you have levels. So, if you used a short rest and then it was no longer available after that, you may have been level 1. Am I right?
There are lots of other mechanics that use the short rest other than spending hit dice. Limiting short rests to how many hit dice you have to spend would be awful. Gimps the entire Warlock class into pretty much just a cantrip turret. Though Rangers, Paladins, Wizards, and Druids also have reasons to short rest even if they don't need to spend any hit dice at all. Not to mention magic items that may recharge on short rest.
