What argument can I have for this question should people choose an occupation based on their personal interest?

Some should. You chose a job so you can get money, not for fun. Most people later on find it "fun" or interesting I guess. You are not always going to find one that interests you at the moment.

I think yes but they need to know if they are fully capable of doing the occupation. They should know if it will give them enough money to buy necessities. People should think about personal interest because if tou don't later on you are gokng to want go quit if you dont enjoy it.