But once you convert your coins to fiat, you need to deposit the resulting fiat in your bank account. I am not sure how much it is going to cost, but I suspect that it is much more expensive than the exchange fees and on top of that this process can take a few weeks to complete.
Then that is a problem with the fiat banking system. If you are paying fees to deposit fiat in your accounts, then you'll also be paying those fees when depositing fiat customers have paid you with.
Why should I care as long as I'm not made to pay for it?
Because your initial point was "bitcoin is too expensive". Bitcoin is actually far cheaper for merchants to use than credit cards. If more people understood this, then it could help adoption
Okay, let's rephrase myself
And put more emphasis on "Bitcoin is too expensive for the end users". Really, what difference does it make if it is cheaper for merchants but buyers are still not going to use it anyway and partly because it is too costly for them to transact with it (it is not the only reason but yet a significant one)? Further, I can't really grasp how understanding this could potentially help adoption. Will such understanding inexplicably make transactions cheaper? Care to explain?
It is not merchants who have the say in these matters. It is buyers. So if buyers want to pay with credit cards (or otherwise), merchants will readily pay these excessive fees to Visa and its likes.
It goes both ways. If credit card companies suddenly put their processing fees up to 10%, you can bet merchants would either stop using them, or make prices more expensive for using credit cards, regardless of what the customer wanted
They are not fools, and we shouldn't expect them to make rash moves that will cost them dear