"System Package" vs "System Service"

[Raghav Gururajan]

Hello Guix!

I have this confusion/doubt. What is the difference between declaring
something as "System Package" vs "System Service" in the Guix System
Configuration?

For example, if I have application[s] (installed as user or in system)
that uses Tor to connect to Internet via Tor Network; is it better to
declare "tor" package under system packages (or install as user) or to
declare "tor-service-type" (with default configuration) under system
services? What actually happens between the former and latter scenario?

Thank you!

Regards,
RG.