Not necessarily. There are traders who are successful crypto traders and trade part-time. Success depends on your financial goals and wins, so there is no definite answer to it. Your trading method is also important here. If you're a long time trader, you require more hours.
Correct, however those that are part-time traders and that are successful will tend to gravitate to becoming full time traders eventually, after all it makes the most sense, if you have a jog that does not have such a good pay and you can obtain way more with your trading skills then logic dictates that you leave the job that does not pay you much and instead you concentrate yourself in becoming a trader, as not only you will earn more money but you will also have more free time as well.