It's not fully unnecessary step in-between when fraud is involved.
If someone hacks you/deceives you and somehow they got $5000 from your debit card, then your bank account is $5000 smaller. That can impact your ability to pay rent, or whatever you needed those $5000 for.
If it's via credit card, you have a decent amount of time to contest and resolve the issue.
the disputed amount should effectively be removed from your balance or offset by a temporary provisional credit until the investigation is completed