If you use the builtin configuration file in a pre-commit hook, you don't know which version of gitleaks the user has.
It may be that starting from a specific version a particular kind of leak would be caught, but there is little way to control which version every developer has on their machine.

[extend]
useDefault = true

It might be sensible to also specify the minimum gitleaks version that has to be present, to make sure that the developer as an up-to-date version.

[extend]
useDefault = true
minVersion = 8.23.3

You can do the check on the server after the commit was pushed, but then the leak is already on the server.

(very low prio, the issue can't be closed if generates too much trouble)

cc @zricethezav