^ Yes, it will be easy for the fighters to follow simple rules. Because in the heat of the moment, it is very easy to actually do something that you are not supposed to. So I also think that the rules like 90-degree elbow or shit like that should actually not exist. Either he can throw and connect elbow or he can't. There should not be any in-between. But we don't make the rules so the fighters will have to actually follow the rules. The sad part is we have seen a lot of fighters lose the belt because of these rules. And many of the times if not all, they were unintentional.
That's why apart from practicing fighting skills, UFC fighters also need to know several rules set by the UFC to avoid violations and point deductions. Each promoter has slightly different rules. Yes, as said, in the PFL all elbow attacks are illegal and that will make Muaythai fighters a little difficult because elbows are one of their main weapons. In the UFC, attacking with the feet while both fighters' knees are on the canvas is a violation and I found out about that rule during Aljo vs Yan which caused Yan to lose his belt.