Anonymous vs false IDs

There is a lot of effort being put into creating tools to mask identities. I'm curious why people don't go a different route - creating a false electronic identity? If you have control over your own system, it is easy enough to create an account. Lacking that, there are a lot of companies out there offering low cost accounts on Unix systems with full Internet access. Why not get an account in a different name rather than using anonymous remailers? I can see some reasons for going both routes, I'm just curious as to other people's reasons. -David