The non download bingo games are called flash games. Flash games don't require you to download any software to play it so if you are at your workplace or on an Internet café PC you can not download to, you can still play these types of bingo games.
Some big bandwidth flash games will usually have quite cool Bingo Game Graphics because they don't have to worry about designing the program to be small enough to download. Because non download bingo games are played directly from the server where they stay they will usually be susceptible to internet traffic. This means if many bingo players and other gamblers are on that server at any given time the games will be very slow and the experience will not be so much fun. Also, flash games have less encryption on them.
Slow Bingo Game
Also while you are playing non download bingo games, it is constantly uploading and downloading info to your PC, so you are using greater bandwidth while playing than a download game would. This is also true if you are trying to download other things from the internet at the same time you are playing the game. If you have a slow computer or internet connection you might have lagging times and this might frustrate you and your fellow Bingo Players.
Download Bingo Pros and Cons
Download bingo games are preferred for several reasons. They offer greater protection for the bingo user by using a more secure connection type with the bingo server. Because these games run directly from your computer they will run smoother and faster. Also, there is normally a better selection of games in a download bingo site than in a flash site, plus with a download bingo site you can quickly switch from game to game. In a bingo flash site you would need to stop your connection and then click to open another bingo game.
Which is Better, Download or Non Download Bingo?
When it comes down to it, it all depends on personal preference. Personally I prefer playing download bingo games because they feel safer, but I know many people that want to play bingo from work and don't want to get into trouble for having the casino software on the company PCs, so they like the Flash Casinos.
One thing I have learned is that it is a good idea to play multi player bingo games at flash bingo sites. This is because you all have to log into the same server as your friend for you to all play together but to do it from a download game you would all have to all play from 1 of the player's computers.