@mtan In truth I’m still testing what works best for my particular community. Today is literally day two of the program that I’m running on a private invite-only Discourse and so I’m still open to experimentation as I only have 12 members.
The current hypothesis I suppose is… voting is on the value of a topic, whereas likes as per What are "Likes"? is for expressing agreement, support etc. to another user.
I’m waiting to see if there is any particular preference for either. So far, members seem to be using the like function more, probably because they are more familiar with it, thanks to Facebook etc.