The cloud distribution point may be more accessible to people depending on your situation, if you have a lot of remote workers or a lot of laptops people use outside the office. Also perhaps it's easier for you to setup than getting a Mac Mini and setting up a fileshare.

Right now there is no relationship between an AWS DP and a local DP, ahem JAMF, but you can specify distribution points based on a device's network segment. Keeping in mind there is a small time period when a device is on a different network but hasn't checked in yet where it may go to the wrong DP.

so there is no relationship? you cant replicate?

You can replicate but a computer can not use a cloud DP as backup DP and vice versa

are you using the JSS are your primary JSS? that would be my goal ultimately. I want to still keep my JSS on prem, and have my clients check in...... externally.

@wmateo What you want for that case is a Maser JSS and a JSS running in limited access mode sitting in your dmz.
As per this article.