It seems there is no such thing as hobbyist artist, or weekend artist. Have you ever heard about a amateur artist? They would't say such thing because it would sound pretentious. Even among professional photographers, writers or singer they seems to worry about holding the "Artist" title themselves.
It is weird how a word that nobody can define with precision, or even agree on what is or not art, can have such high status. It would not be possible to agree that anybody in the artistic field is an artist? If not, why?
Since there is no consensus on what exactly is art and who exactly is an artist, I guess the door is open to anybody. And this is why I like this quote from Amanda Palmer:
There’s no “correct path” to becoming a real artist. You might think you’ll gain legitimacy by going to university, getting published, getting signed to a record label. But it’s all bullshit, and it’s all in your head. You’re an artist when you say you are. And you’re a good artist when you make somebody else experience or feel something deep or unexpected. (Amanda Palmer)