In reply to Andy Hardy:
The games climbers play are arbitrary and nonsensical !
Yes it makes the climbing harder but without any of it, as a community, there is "almost" a consensus that it then becomes dry-tooling. As a nation your forebears have decided that DT was not on and to "almost" adhere to Patey's 3 rules:
1) easier with sharp things than without (DT is NOT always so).
2) frozen
3) white
There is some thinking behind this, I agree with them yet I would still posit that it's arbitrary:
I could wait for summer, I could walk from the back to reach the top.
That is not however, what I want when I go climbing in winter. I want adventure and challenge, I want a puzzle to sort out starting at home in deciding whether it'll be in. Some climbs are best left alone if there's very deep rime as they will become too hard and if you're a slow mortal like me it would be a strategic mistake. I have never climbed rime, it may have been a useful addition to stop axe wobbling, front points losing purchase on a few isolated occasions.
But yes you are right, it is an impediment, but a sought and cherished one! And as Tricadam says it's pretty too!