They are worth it, if you have the time and patience.
For killing time, or getting even with the MTT world after just finishing OTM, free-rolls are worth it. But going into one, you know the
odds or ITM, the time required.
Most days, a player doesn't have the time to put into a free-roll, in that case, it's not worth it.
But when you get super close to the money, and lose, free-rolls can help you decompress, in a game you're not risking anything. The answer in this case is, free-rolls are worth it.