I agree with this because it is what I am doing right now in addition to my fulltime job, which is really not enough, but I have seen a lot of people who have found that their side jobs are bringing in more money, and as a result, they have decided to quit their fulltime jobs and devote their time fulltime to their side jobs, a good example of this is running a business, which is why you have a full time job and a side job. I have a lot of friends who quit their jobs to devote their time and energy to their businesses, and they have become extremely successful as a result.
devoting time, effort and money to develop a business is a good thing, i've done that and now my business is quite smooth. but the problem is when we see people leaving their main job just to focus on unstable side jobs
(like bounty or other freelance). if the side job you are currently working on cannot guarantee your long-term income then don't leave your main job unless you are ready to build a business.