I go to the CC final every year... not missed one for over 30 years...
It's because it's 'away' is the main attraction. A lads weekend away to drink beer, eat curries and watch a bit of Rugby
It's just the whole craic that I enjoy, be the venue be in London, Cardiff or Edinburgh, it doesn't really matter. In fact, I enjoy it more as a neutral when Wigan aren't there!
Going to Old Trafford isn't the same (to me), being a day trip to watch rugby with a couple of beers before, after and during the match... just like it is watching any SL or cup game, (With the exception of Catalans away, which is also a bit of a holiday
) albeit with more atmosphere.