I have seen similar saws on Ebay and in some of my tractor books. Most had at least a table to set the log or board on. They did not look much safer.
However, even with the safety shields on them, circular saws, tables saws ect are kinda scary too if you think about it. Or, look at a drill or drill press; imagine getting caught up in one of those. Or, a chainsaw...
We have safer tools now, but still have lots of potentail for injury.