[GuB-42]

You can get the best of both words with good power management. Fast charging can be disabled on my phone. I also know some laptops where you can limit the charge to ~70%, intended for case where it is always plugged in and you rarely need the battery. Some phones try to be smart, taking into account the time you set up the alarm for instance.

The idea is to have fast charging for emergencies and slow charging for regular overnight charging.

And the thing you plug into the wall isn't actually a charger, it is a power supply. The real charger is in the phone, and that's the one that decides if it needs fast or slow charging, taking into account what the power supply can deliver.