Beneficial? Probably, to some extent. Worth it? Totally up to you. They can give you a nice perspective on how your mixes will translate, especially in the mid-region, but in my opinion they are quite over hyped, mostly by people who are stuck to them for whatever nostalgic reasons and people who have never actually worked on them. If you sold your HS80's and Rokits and added the $400 on top, you could grab a great pair of nearfields.
Some people always pull out the age-old "tons of hit records were mixed on NS10's" argument. Yeah, so were tons and tons of utterly crap albums.