This is nothing new and there are thousands of examples where it can work. The key is to limit it to people who travel on a very regular basis. If you do this 40 times per year and have to throw away a couple of tickets because positioning flights don't work out, you have likely come out ahead because you have saved on 38 trips. But, if you do this once, the risks may not be worth it.

Don't forget that there is almost no travel interruption insurance which covers a transfer between tickets as opposed to a connection.