ok ..... getting back to the words 'pointless cross' ------- which is sort of contradictory in itself - because the results of a cross are generally unknown until the cross is made. So in order to find out what possible results there are ------ the cross needs to be done ....... so that's the point. So not pointless to begin with obviously.
It may not be apparent, but some plants have unique traits that is not just looks. Even among Brassavola nodosa, there is one variety that is able to bloom under lower light than others.
While it may seem pointless, back-crossing can yield potentially better plants with more vigor or desired traits. Wouldn't you like a nodosa breed that blooms every month?