It's not really significant for RSA at all. It is likely that no human (as far as we recognise the species) will ever generate RSA primes of this form randomly,

It's not really significant for RSA at all. It is likely that no human (as far as we recognise the species) will ever generate RSA primes of this form randomly, if standard tools are used. It's been known for a very long time that there are many extremely sparse classes of primes which general factoring algorithms will extract as factors very quickly. For example, some general factoring algorithms will factor numbers of the form (a^m+b)(a^n+c) for small a, b and c and m and n fairly close. But this is an extremely sparse class. You could generate billions of such sparse classes (and check them all by brute force), but it's still unfathomably unlikely you would find RSA primes in the wild of any of these forms, if they were generated by reasonable implementations.