What you're looking at are called "straight-pull" spokes. The theory is that without the bend, the spoke can be stronger, which means higher tensions, which is supposed to mean a stronger wheel. It's an everything old is new again idea, that gets reinvented every fifteen or twenty years for the last 120 years. There may, or may not be, advantages to straight pull spokes. There are certainly disadvantages, chief among them cost, and they're mostly racing designs (so light weight, with less load-carrying capacity, and very few choices in rims and hubs. 255 isn't really that much, and there are any number of road bikes that can carry that.