Depends what you mean by "worth it". If you need it, it's worth it, if you don't it's wasted.
Musescore is an open source notation software which you may or may not like, which funds itself with the website. I like the I idea, but in general I don't particularly like those scores, which I believe are made by volunteers, so quality is hit-or-miss.
MusicNotes is a non-traditional publisher, which hires people and at least in part vets their content. I personally know one person who posts his scores there and they are very good (can't vouch for other artists). However I've always had troubles purchasing from that shop, I think they are too aggressive with their DRM and I would not recommend them blindly. So consider that, especially if you use Linux, and if you are okay with that and you like what they offer....