I have seen almost all circuits with crystals that they put the crystal laid down and weld it to tie it down. I think they do it beacause don't want the crystal's pins to break from some mistaken moves. like have with capacitors and trasistors (when manipuling the board sometime we hit them).

But i was thinking if that was a good reason to do so. Because if there is no reason, the space is badly used.

 

I beleave they also do it to ground the case, or hold it down from other vibrations.