Middle school wrestling is some athletes first exposure to the sport so it is important. For some it is practice right after the school day lets out or just the timing of when these kids can get to a practice and get picked up after school. In many cases it may not be as competitive as club wrestling - but it can still serve as a stepping stone to high school wrestling and can be very valuable. Some towns/cities only have middle school wrestling and no clubs - that may be the case in some towns. Also, there are costs to consider - fees, uniforms, travel, etc., - in many cases middle school wrestling may be the only viable option where the school districts can provide a coach, practice facility, dual meets, etc. Middle school can offer the value of a team concept with duals and tournament scoring.
Some exposure is better then no exposure to the sport.