More opinions are always good. I think you'll find that the prevailing opinion around here is that Bettas need 2+gallons of water, heated.
People tend to get sensitive with the word "vase", it brings to mind a small cramped thing crowded with plants. It may be better to call it a "Decorative container" or "Designer Aquarium" with a semi-aquatic plant addition.
Really the form of the aquarium doesn't matter as long as it has at least 1 gallon of swimming space (many say 2 but most breeders use 1 and their fish are happy and healthy) and a heater.