Just so you know, many consider ramshorn snails to be pest snails. They, like the bladder snails can reproduce fast if food is plentiful.
If you like the little guy then keep him, he shouldn't harm your plants, and won't hurt your betta, about the worst that will happen is you'll have to periodically thin out the snail numbers. You could even set up a 1 gal tank just for him and let him live in it. You shouldn't have to heat it unless you keep your house really cold.