Not a life threatening matter I would suppose as I have seen them do just fine in bowls, but they are like most aquatic life and do produce ammonia so they would probably appreciate the cleaner and fresher water. Frequent water changes in a bowl will keep them going though.
Thanks. I was just wondering because I believe that the tank that I have my snail in right now is malfunctioning and I don't want something to happen to him so I thought about moving him to a regular bowl until after I move and could get him another tank.
I don't know how sensitive snails are to ammonia, but they do produce massive amounts of waste. The ammonia would build up really fast in an unfiltered bowl. I would never keep a snail without a filter. Of course, I don't think your snail will die of a temporary filter malfunction. Just get a new one if it doesn't work and do lots of water changes in the mean time.
I have seen pretty big bowls and those with fairly straight sides. If this is the case there are small tank filters that would be very inexpensive and I have used one that is excellent. It is the easiest to set up and run and change media in and does not take up space in the bowl. Here is the link and it is really neat there is even a small light you can get for the bowls. You can make a nice sized bowl just like a small sized tank and it is beautiful.