It’s also fundamentally different. There are protections, but they depend on you being aware of the activity to avoid impact. Basically, in the event of fraud with a credit card, Chase or AMEX have a problem. With a debit card you have a problem until the resolve it. In the meantime, your payments and checks may not clear or hit overdraft.
As long as you can control your spending, credit cards are a real superpower for consumers.
Hence why cash discounts are a thing (and yes they're legal again).
It's not a great system but it's what we have so using debit instead of credit does mean losing out.
Especially service companies. They tend to quote out "cash" (aka check/bank transfer) price and then add another 5% or so if you want to pay via card. There of course is very often an even cheaper "actual cash" price too you need to ask for if you are so inclined.
This is no longer a thing, there was a settlement with Visa/MC that removed this provision from their merchant contracts. You are now allowed to pass on transaction fees if you feel like it as a merchant.
It was also never illegal. It simply was part of the contract to do accept Visa/MC/Amex and they'd close your merchant account if you got caught doing it.