"Show battery percentage" belongs in Control Center, not Tweaks.
There can be many reasons for people wanting to see battery percentage, While I understand it may not be shown by default, it is an important enough function to be present in settings as a toggle.
One of my friends, for instance, had an old laptop with a faulty battery that would abruptly shut down below a certain threshold. He used battery percentage as a method to counter that and act before it's too late.