I think the problem is that the IBJJF and it's rules have become synonymous with BJJ and it's rules. At least in many schools I have seen, you are forced to roll under IBJJF rules..whether you compete or not.
And to me, training jiu jitsu under IBJJF rules is not training jiu jitsu..it is training a specific subset of jiu jitsu moves that are allowed in particular competitions. It's jiu jitsu with explicit restrictions IMO.
In this way, the lower 3/5 and 4/5ths of the belt spectrum tend to train "Northern-Style" jiu jitsu and ignore much of the lower half of the body.
This is all just and observation and opinion of course. Nothing more.
well, it is for safety.
It is better to have a set of rules so at least you know what to expect.
I know a brasilian guy that train with all leg locks from white belt in Brasil (including heel hooks).
It would be cool to find other clubs that do such rules.
In my club, you can do subs on someone that level.
so a white belt can knee bar a brown and vice versa but a white belt cannot knee bar a while belt.
I am also aware that it is limiting people skills as according to some people it should take you 7 years to brown belt which means most people would have quit by then.