It's still better than putting it in the same, expected spot. Plus, port scanning is often a red flag behavior (i.e. it's against terms of service in EC2 to perform it from one of their machines), and it can be detected.
It's like putting your key under your door mat vs. some loose brick near your back door. Sure, someone can still find it (I don't recommend the real-life equivalent), but assuming you have a camera and/or nosey neighbors, there's a good chance the presumed invader is going to look suspicious enough to garner unwanted attention.
Oops I didn't know about the scanning thing. I often do this from my hosted VPS to my other systems, to make sure all ports that I plan to have closed are actually closed.
Especially when it involves IPv6 networks and each internal device has its own IP, this can involve a lot of scanning. I haven't had any complaints but good point, I could get banned for that.
