Cheese race wouldn't let a user combo all the garbage lines and leave them with an empty board. Very rarely detrimental but still the case.
The minimum for Jstris is 3 lines I believe. Maybe subject to change for reimplementation but that would cause an imbalance in the information available to players, messing with comparing cross-client runs. Just passing this on from someone who's tried the mode.
Discord mobile ain't letting me edit the message
if the user hits a roadblock in clearing cheese it sounds more like an issue and not a feature