I should clarify, it is only important (implicitly important I should add) if you're trying to project certain things. You have a negative coefficient for iCF/60 and a positive one for ixGF/60 if you're trying to project P/60, GF/60, GD/60, xGF/60, xGD/60, xGF%Rel, while both are positive for G/60, CF/60, CD/60 and CF%Rel. The balance between the coefficients has the consequence that many shot attempts with high ixFsh% is the best, though many attempts with a decent ixFsh% is likely better than very few attempts with a high ixFsh%. Firing away low-danger attempts or not getting your shots through (blocked shot = 0% "danger") counts as a negative.
I've got a few off the cuff rationales as to why:
- A shot attempt is something that has a likelihood of ending possession - especially if blocked. I can see how taking a low-danger shot instead of creating a better opportunity would be detrimental to xGF%.
- Being able to get into positions to put up high ixGF numbers indicates talent, especially if the player is able to do so without tanking his CF%/xGF%. Any defenceman can stand at the blue line and throw pucks at the net as soon as he gets them.