You're still installing the program directly from github of course, instead of a source where hopefully a third party has also looked at it (like a package repository). But this is a lot better than the curl | sh pattern.
And an executable can do exactly the same as a shell script. The point is that whatever you're executing isn't verified, whether it's a shell script or a binary.
The GP said:
> This should be an ordinary app bundle to drop into /Applications
There is no difference between downloading an app bundle that you drop into /Applications, and curling a binary that you put in /usr/local/bin/