Multiple small charges harmful?
The possible reason why someone want to charge a short while is because they have to use it constantly till battery is low, then charge again.

Such usage will allow battery goes into constant current charging frequently. Keep using the phone and it will heat up, then starts charging and continue heating the batt. 

The battery lifespan may get even worse if dodgy design is being implement in the phone. Some manufacturer claim how fast you can charge your phone but all this new features will make you replace the batteries often.