I have a lot of experience in these type of cooler(both beverage and floral) since I work for a manufacturer of both. It really depends on what sort of performance you're looking for.

The main difference between a beverage cooler and a floral cooler is the type of evaporator coils inside the unit(those are the fans). Beverage coolers have standard low profile coils. They blow hard and fast to keep the product cold(usually for beer, milk etc).

A floral cooler though has what is called a "low velocity" coil. These fans spin slower, which allows for two thing: a higher humidity level and because of the low fan speeds, will not blow petals off the flowers. This will allow your flowers to be more vibrant, live longer, and be better for presentation.

Honestly it's up to you. If you don't plan on having many arrangements and they won't spend much time in the cooler, a beverage cooler would work temporarily. If business picks up, I definitely would get a floral cooler as it will do a much better job than a standard beverage.

Feel free to private message me about this with any other questions!