RA in American universities is generally paid by professors' research funds, and they are subsidized all year round. They can attend academic conferences without taking exams.
The allowance of American scholarship RA is paid by the professor's research funds, and the legal working time is 20 hours per week. RA has a lot of freedom, so it can work around the clock when it is not busy with homework, and can concentrate on preparing for the exam when it is near. It is worth mentioning that there are certain risks in doing RA. Because some professors don't have enough funds to pay their students a few years' allowance, they still recruit students to do RA. However, when the students were halfway through school, the professor's funds ran out, and then the professor told the students that he had no money, so the students were miserable. Students suddenly have no source of income, just like ants on hot bricks looking for money everywhere, or directly doing manual labor to earn money. At present, this situation happens from time to time in American universities, which causes students to be extremely passive, and often forces students to re-find professors who can provide RA, or even change majors or transfer schools. Although this is not a common phenomenon, it does exist objectively. The way to avoid this situation is that students should fully understand the professor's financial situation before accepting the offer. Usually, responsible professors will explain their projects and funds to students when they formally enroll students. If the professor says nothing about his financial situation, students should take the initiative to ask, so as to avoid being passive in the future, because once the professor has no money to give students an allowance, it is the students themselves who suffer passively.