Hi Janos,
All are valid points that you have mentioned 
But still rsync is not just a copy process it syncs all the online changes as well so by the end of activity you get everything same as source. Since *ix platforms just use file and the links (no registries), it is quicker and better solution to build new systems (again if you are comfort).
I did this to build new systems as well (non-prod systems), it can be done for SAP(instance) too.
Yes - Option selection is Narayana's.
Regards,
Nick Loy