There was a similar discussion to this on about 3 years ago, but I don't feel like digging it up. In a nutshell, all the reasons you've listed PLUS everything in the other posts...all lead up to the same thing: Most leather shops wind up with at least two sewing machines, and often times 3-4. The machines are quite capable, but if you're setting up for any kind of production speed, a 'one machine shop' isn't practical. It's much more economical and practical to have secondary and tertiary machines set up so all you have to do is move from one to the other. One big machine, one medium machine, and a patcher.....that's about the requirements if you're planning on having a dedicated leather shop. Of course, if you're just a hobbiest then it doesn't make sense to have the extra money tied up multiple machines.