Is it difficult to work around cellulose installation?
Blown-in cellulose insulation is fluffy stuff. It doesn't harden. You can shovel it out of the way if you need to work in the attic; you just need to redistribute it evenly back into place when you're done. So it makes working in that space something of a nuisance, but not worse than that. 

(Assuming a traditional attic. If yours is a low-roof crawlspace, moving the blown-in around may be more of a problem, just because there's less space to move it into.)