If your trying to get into it with a small budget, that might be the way to go until you build enough work for it. Nothing worse than dropping money on a piece of equipment and then years later still not having enough work to justify it.
We picked up a slide in unit for one of our trucks with the idea that we would use it to build a route, then once demand justified it, we would buy a new dedicated sweeper truck such as the one you posted (but new/newer). We never built up another work to do so. Now the slide in unit gets used maybe 12 times a year. When Other small sweeping contractors we know have a piece of equipment go down or fall behind schedule and sub us to help out.
Why do people not respect us as they do other tradesmen? Because every Tom, Dick, and Harry doesn't think he can be a plumber or electrician!