Scrum Master: experience and recruitment (in Europe)

1. What does happen if the candidate has 3 years of experience? Isn't that enough?

It could be more than enough, or nowhere near enough.

2. What does happen if the candidate worked in a Scrum Team for several years as a Developer, could/should some of these years be considered as experience in the framework and/or as Scrum Master?

It could be of great relevance, or of very little at all.

Perhaps that job description says more about the organization, and the constraints it uses to try and quantify complexity, including people, than it does about the person they are trying to recruit.

If they want the Scrum master with 5 years experience they will probably not hire Scrum master with 3 years experience. Or will, if the Scrum master with 5 years experience will not show up

Years of experience isn't the worst I can remember among Scrum and Agile job advertisent's in Europe

I can remember few atrocious job descriptions

Let me just recall few(not exact quotes because I just saying what I remember)

"Product owner wanted to work on Product backlog with a team of other product owners"

"Scrum master wanted. Job description-should maintain Jira documentation for the team, collect the status reports at daily stand up and report progress to the Product owner"

"Scrum Kanban specialist wanted to set up daily standups and manage the team of programmers"

"Scrum supervisor wanted"

That juts a few I remember, can recall more. Don't ask who are the last two positions, I don't know.