Isn't this about operating within the rules and being practical at the same time.
Suppose you are due to operate say hkg-lhr but the weather at lhr is planned to be below limits for your arrival. However, man is forecast cavok for your arrival time.
You cannot flight plan hkg-lhr but you can plan hkg-man with say edi as alternate.
Is it not better to get airborne for man and en-route refile to lhr when the forecast changes and the weather for your arrival is such that it will be above limits?
Done it from time to time and used the en-route alternate rules to maximise payload.