Word games like crossword puzzles and SCRABBLEÂ® exercise your lexical recall (memory for words that name things), attention, memory, and pattern recognition. They can help maintain your vocabulary and avoid the frustrating tip-of-the-tongue phenomenon that all of us experience from time to time. Sudoko is not a mathematics game in that you don’t actually manipulate the numbers as mathematical entities, but it is a pattern recognition game using symbols (numbers). A very legitimate reason to play casual games is that they can be social and fun – which is good for reducing stress.
The drawbacks to puzzles and games is that they are hard to calibrate to ensure increasing challenge, and they generally only exercise a limited number of brain functions.
So by all means, do puzzles if you enjoy them! But be sure to push yourself to keep finding harder ones that fall just short of frustrating you. Also, just as you cross train your voluntary muscles, be sure to cross train your mental muscles by balancing your workout with other types of mental work (motor coordination, auditory, working memory, planning, etc.). The computerized programs make it easier for you in the sense that they are individually calibrated for you to employ novelty, variety, challenge, and practice to exercise your brain more thoroughly in each session.
Further reading on language production, comprehension, and goofs: