Pump brands and strength are a personal choice that have many variables.
If the tank is in a room where other things happen (like people watching TV or sleeping), it may be about noise. Some pumps are loud, from the motor or vibration, some are quiet, and may influence your choice,
some pumps need to be bolted to a heavy object like a brick to keep them quiet.
Some pumps suck electricity like crazy, and may be an influence, because of energy cost.
Some species of fish need more flow/current than others, this may influence your choice.
I keep rheophyllic species, so this is a major factor in how I choose how large and how much head pressure pumps provide.
You may also intend on putting more than one tank on a sump later on, so getting a larger pump in the beginning may be a a money saver in the end.
There are probably many more reasons.