If you want to run your python script, let's say every day at 6 pm, is it better to go with a crontab entry or with a Advanced Python Scheduler solution regarding to power, memory, cpu ... consumption?
In my eyes doing a crone job is therefore better, because I do not see the advantage of permanently running an Advanced Python Scheduler.
You should probably use cron if two conditions are met;

It is available on all platforms your code needs to run on.
Starting a script on a set time is sufficient for your needs.

Mirroring these are two reasons to build your own solution:

Your program needs to be portable across many operating systems, including those that don't have cron available. (like ms-windows)
You need to schedule things in a way other than on a set start time. E.g. on a set interval, or if some other condition it met.
Cron job vs Advanced Python Scheduler