>>rubyn0+(OP)
Neat! But it's not obviously a bad idea. You have a TLS connection with the site you're downloading from. `curl | bash` is no worse than downloading a .dmg or .deb from the same server would be.
>>throwa+k4
dpkg doesn't stop you overwriting system files in a post-install shell script, as far as I know? Which is the way that a malicious package would choose to do it. I don't think dpkg performs any meaningful security review in the way you describe.