Which is easier to learn? Which is easier to apply?
I don't think it's a case of which is easier. Either is easy enough - if somebody teaches you how. My guess is that the majority of users who need to increase text size are older folk. These people didn't learn how to use a computer at school - they've had to pick it up somehow on their own. They might have gone to classes - but how many basic computer classes teach accessibility issues? None I've come across. They don't, because they cater for the majority, who don't need to know.
When I show somebody how to change their font size, I show them both how to zoom and how to set it in the preferences. In my opinion, it's easier to set it once, in the preferences, than have to zoom every site you visit.
Originally Posted by itmitică
Unless he doesn't know what is doing and make things worse. Do you think there are many who know that: using proper settings?
I'm not sure what you mean by that. I have to assume that anybody who has changed their preferences has done so in a way that suits them. It's not for me to decide if they've done it right or wrong.