It really depends on how you pull it off.
For example, you've seen probably on Youtube thumbnails like these:

Those are some examples of pointless videos. Usually comes with a thumbnail having the following things in it: Giving away the content, having sometimes those emojis in it 

, asking questions, having the people in the video doing that dumb open mouth in shock, surprise which can be ANNOYING TO HELL IF EVERY VIDEO HAS IT!!...
...Sorry. It's just frustrating, Jesus. Sitting through the whole 10+ more minutes thing with someone who has a personality more boring than plain bread feels like a waste of time.
Now I'm going to show a clickbait thumbnail well done, in my opinion:

What is it saying to the unknown viewer? You're right, nothing.
Who is this person? What is good drama, and how are they involved with it?
The thing is, doing clickbait without being annoying and having some mystery behind it can draw the curiosity of new viewers in better than the hyperactive ones. I think that doing more of these can be better, but that's just my opinion.