Fully agree.
The best way is to either use JProchazka’s script, or in case it has still unresolved bugs, use totally manual method to know exactly which step has the problem.
Other than cpu architecture problem, another problem is that Ubuntu & Debian have many versions & codenames, which are not covered in “piaware_builder”. The OP of this thread has Ubuntu 18.10, and its codename is “cosmic”, which is not covered in piaware_builder/sensible-build.sh. This will result in failure of JP’s script as well as manual method I have posted here.
Today morning I could successfully install Piaware on Ubuntu 18.10 Cosmic by cheating 
the build script to make it think the distro is “bionic”.
Instead of detecting codename by command CODENAME=(`lsb_release -sc`), I used CODENAME=“bionic”. Please see this post for details.