The significance is that there's a physical limit to the amount of information that can be stored in a given space. I believe this fact made the Lightning Network inevitable because, regardless of the chosen blocksize, we would hit that bottleneck eventually.

Also, I wanted to point out that Bitcoin is not Turing complete because it does not have infinite loops or recursion. i.e. while you can solve an arbitrary problem instance from a class of problems with a specific Bitcoin script, you cannot solve that class of problem with a single Bitcoin Script.