The reason for not using Google + vanity URLs because the spammers could lead to find the email addresses of millions of Google users + (as many accounts linked to Google's Gmail account).
Of course, this leads to a problem: you do not want to tell people to write in a long string of numbers to find your profile + Google. That's where comes in. This small simple application Gplus.to lets you create a short URL for Google + page, making it easy to share with your friends. Mine, for example, is Gplus. to / benparr, which is much easier to remember than a strong random numbers.
Gplus.to fills a gap that Google + not currently addressed.