Agreed, when such UI are represented like this, the user can only approximate or guess where that maximum is at, especially if there are no reference to other on-screen UI to compare to.
Also, besides a continuous bar, when it comes to repeated icons like this (4/5):
●●●●
the empty are shown as outlines, or as silhouettes in a similar way (4 filled + 1 empty = 5 total icons):
●●●●○
or:
●●●●◌
If it were numbers:
- Every value displayed as digits are always distinct (even by a little), because it is based on symbols. It is also easy to remember the maximum if the max isn't displayed when the current value X is equal to max.
- Percentage is pretty obvious of where is the maximum is.