Afaik, the KR site only allows for cards issued by Korean banks, but you can probably use google payments if you have an android.
You can switch the app to the KR version through your language settings and when buying with google pay the won/yourcurrency exchange will be auto, but if you're totally unfamiliar with Korean you'll get lost.
This would certainly be better. This is no different than those "Choices" stories apps where all the important decisions and interesting parts of the story are hidden behind microtransactions that'll cost you 50+ for a decent ending to the story. Being able to subscribe for a set period instead of eventually blowings 100s for a few pages that wouldn't even equal the status of full printed manga is ridiculous. I'm fine with wanting support for artists but this isn't the way.
I'm sure many people agree with this but it would be so much better if there was a monthly subscription so that you pay a certain amount for a month and you can read the comics. But why would they do that when instead they'd be getting much more money from getting customers to buy individual chapters??
Oh small query, how does one pay from an international credit card on the KOREAN lezhin? I probably won't be able to buy anyways because I don't want my dad to find out, but I'm just awfully curious.