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 think its 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 its worth it, but I want to upload some bounties. Id like to have a lot of patterns, so I collect gold coins to get the most may offer for patterns.