In my opinion, the Meyers Briggs is useful mainly because it can help people become more self-aware and more empathetic toward others.
I've observed that in a group of 15 people who just got their Meyers Briggs results, several usually think it was uncannily accurate, and a few are immediately defensive because the result does not jive with their self-perception (usually because the personality type is described as similar to some unsavory characters from history). When I read articles criticizing Meyers Briggs, I always assume it was written by one of these people.
If you are in a relationship, one interesting game to play with your significant other is to take the Meyers Briggs test and then read some of the stuff that has been written about relationship compatibility through the Meyers Briggs lens. I've found it to be quite accurate for many couples I know. There is also a very amusing book called Please Understand me II which has detailed write-ups about the characteristics of each type. It's great for parties to read out loud everyone's results over a glass of wine.
IMHO Personality tests are useful mainly to encourage self-awareness, introspection and empathy. As a Meyers Briggs ENTP I find the descriptions of an ENTP personality flattering and desirable. I suspect nearly any type would find their own type description equally flattering and desirable.