but is the subsonic really more accurate then the high velocity rounds?
I think the explanation is generally that when a supersonic bullet slows down and comes back through the sound barrier it slightly destabilizes, losing accuracy. For the .22LR, this happens roughly around the 70 yard mark. Subsonics avoid that entirely. However, if you shoot at shorter ranges, it's a nonissue.
I imagine the actual answer to your "is it worth it" question has to do with the ranges you shoot at and what you consider acceptable accuracy. If you shoot bullseye at 100 yards, then yes, it probably is worth it. If you shoot squirrels or soda cans at 50 yards, then no, I'd not make a point of it.
Furthermore, there's your own capabilities and those of the rifle to consider. With a box stock 10/22 or other volume produced rifle, there may already be enough "slop" in the accuracy to make negligible the accuracy difference between standard and high velocity loads. If you're shooting something that's been accurized or is otherwise very capable (say, a Volquartsen), then sure, it's probably worth spending a bit more to get the most out of it.
There's just too many variables involved to give a flat answer that works for everybody. Generally, I'd probably say that the vast majority of shooters won't notice any issues at ranges under 75yds, but that's a really general answer and may not apply to you.