Telling someone you have voted (and how you have voted) is not necessary. If you want to give your appreciation, just vote for that post and possibly accept that specific answer.
We want to build a Q/A knowledge base here, and everything that distracts from that is removed. Discussions in comments, 'thanks', giving information about your votes, etc., is all unnecessary information that have no value for the overall information shared on the site.
You can point out a specific part of the answer that was helpful if you want to, that will emphasize it for future users which is helpful.