I agree with you, I find the Like button much more useful than the thank you button. As it has already been stated in this thread, sometimes I cant form enough words to write a small critique, sometimes it doesnt need to when you look at it and go wow, or urghhhhh.....!
So clicking like is/can be better than saying 'great shot'
and sometimes, earlier posters have said everything I would have said anyway so I felt no more need to comment or critique.