Well, explanation/definition is not a good explanation. As you would know, one of the main function of "A って/という B" is to explain that A is the characteristic/attribute (属性) of B, so っての/というの has a nuance to that the clause is talking about a characteristic/an attribute of the preceding noun/phrase/clause in general, something like "things like~". If って/という isn't there, it's just about そこまでして会いたい子がいるの/こと. The difference is subtle (or very delicate) and hard to explain, though.