While a lot of people unfortunately buy these due to ignorance on betta care or just lack of care in general, here are a few reasons why this isn't a good setup for a betta:
1. Small size. Mose people here recommend at least 2,5 gallons for your betta. The vase doesn't have much room for the betta to move around in.
2. No place for a heater, which bettas need. Bettas are tropical fish, so they need warm water.
3. Bad design. Doesn't really look like you can do water changes, feed your betta, or have room for him to breath in that.
At least you came to check before you went to get one! A lot of people don't even bother.