Like them or not, comps are a way of modeling life; they're not going away. Because they are a human endeavor, there will always an element of politicking, disappointment, and ill-feeling. People are people... Here in the US, the size of the comp and the vendor's area is the standard by which everything is measured. The two tend to feed off of each other and attract more attendees. The vast majority of the models are in the comp. Club displays are rare, even at the IPMS Nationals. Many shows have a display only table and they tend to be thinly used. Some will put their models on the comp tables with signs reading 'Display Only'. I'm assuming you all have that option in the UK and Europe.
That said, comps have a singular advantage in that there is a room full of outstanding painters and judges (who are, theoretically, outstanding in their own right) and thus a readily available source for learning how to paint, how to improve your painting, etc. Read all the forums you want, read all the magazine articles and books you want, watch all the videos you want, but nothing beats a hands on, one-on-one with a master at the craft. Don't treat the comp as a judging moment; treat it as a teaching moment with the comp as one big school. You don't need to join the band, just listen to and learn the music.
Nick rightly pointed out that being able to compare your own efforts with those of others is a valid point. A side-by-side comparison is a silent teaching moment in its own right, especially if it's the same piece. Observe, take some notes; then find the owner and grill 'em. And when someone asks you how they can improve their skills, be prepared to spill your guts - or at least introduce them to someone who can help them.
Glen