I have had lots of bounties but only few have been filled. I still think it's worth it though because you might eventually get what you want and if you do a lot of tasks then it's not such a bad loss if it never happens. Would be great if you could get some of hte coins back if you don't get it after a year or something, but it's not so bad this way.
If you really want something I would. Though it does seem, IMHO, the ones who offer the most coins are the ones who people tend to answer. Ad if it is a cross stitch chart ask that it be a good scanned one not a xsd, especially if you do offer a lot of coins for it.
I often ask myself the same thing. I have many bounties up for the pattern in English and only one has been answered in many, many months. I think it would be worth it IF anyone answers the bounty.
I think it's well worth it. I had one of mine filled and was most grateful for receiving it. I think I offered 5000 GC for the one I received and it was worth every one of them!
I do not know whether it's worth it, but I want to upload some bounties. I'd like to have a lot of patterns, so I collect gold coins to get the most may offer for patterns.