How can an adaptable progress display be used?

One proposed use is that Elapsed Beats can be used to organize a song list by its components- Beats Per Minute, and the resulting lengths, (number of beats passed after the song finishes, measured in Ë).

When a person exercises, they need to keep track of their heart rate depending on the type of activity they are doing. 

Elapsed Beats could have a mode where it disables any songs out of range for a desired activity

Sometimes, we need to relax, and we need slow music. Again, the same would be useful.

Who could benefit from this? Personal Trainers, Psychologists, and Music Artists are likely candidates,

although the general public might find it beneficial as well.

Elapsed Beats  doubles as a progress bar with an alternate unit of measurement, and it validates the speed from beginning to end to make sure it matches with your desired state.