Solar charge controllers

INTP:
ELI5, please, why a buck/boost module couldn't or shouldn't be used to regulate voltage of a solar panel instead of a 'charge controller'

Charge controllers come in PWM and MPPT types, where would a buck/boost module fall in terms of efficiency?

Hmmm. This appears top be an orphan posting. We used to build hundreds of the PWM types. All charge controllers will STOP trying to charge when the battery voltage shows charge is complete and will STOP trying to charge when the solar panel input is too low. A buck/boost module will continue to TRY to charge forever.

Paul