Good point Tdol.
A crossword puzzle can be a challenge and a stimulant at the same time whereas word searches are a bit of a time filler. Although, I believe they can be an aid to introducing words not yet discussed and also a bit of a spelling refresher.
When I had classes, both were popular. I used the word search printouts to great effect. I had a class of about 20, and unfortunately their skills ranged from struggling with the ABC right up to playing the game, stump the teacher with this new word I found.
I was able to occupy one group with word searches whilst I spent time with the other. I used crossword puzzles (with cloze clues) as homework.
I don't know why I am rambling on. I think I am stimulated by intermittent pressure on the finger tips.
I am finding it so hard to get my email students to go to my crossword site and attempt some of the puzzles. There is certainly some inbuilt resistance. I have noticed it for a couple of years now.
Any ideas why?