It was neat fan service and an interesting way of including them in the present day timeline somehow.
It isn't as forced as making one of them meet and hook up with one of the current cast just for the sake of keeping shippers of a non existent couple happy.
or as forced as dohee? meeting up with eunji and going crazy over HOT also and becoming co fangirls or them having an extended fight between their fan clubs or something like that. THAT would have seemed forced.