Ow sure;
As noted I am former Harmony Elite guy, and with that I could use Homey to start/end activities, without using the remote. Opening up options to start something based on something totally different. This was due to the Harmony Hub app on Homey.
Also Logitech Harmony can be connected through Google Home for voice commands and I have a bunch setup through the house. They basically start through Homey and trigger the specific flow)
Now with Remote 3, yes I can start things on the remote.
And while you can Trigger using the UnfoldedCircle App on Homey BUT that still means it has to be started on the remote’s end.
But what If I want to start something (a activity/remote) without the remote? Well that is where my curl write-up come in.
Beforehand some more details on Macros;
Basically they are single sequence (run) activities without providing any controls (pages) on the remote. Which can come in quite handy.
On to a few use case examples;
Voice command example 1 - Triggered through Google
Voice command example 2 - Triggered through Google
Macro example - When housemate arrives and im playing music
Macro example - When it’s time to watch the News around dinner time hahaha 
Hope that gives a bit of an idea but in genera the TLDR is; I wanted to have the Remote 3 work hands-on ands hands-off , and with the previous explanation … it can. Opening up quite some options, to combine the reach (integrations/flows etc.) of Homey with it.
So while Remote 3 is a bit more work, it is waaaaayyy more flexible for me then the Harmony Elite. And I couldn’t be more pleased with it.
As for getting battery details
Im unsure how/if the Unfolded API provides that but if it does you could get it with a GET curl request and then store it and use it I guess. I’ll give that look a bit.
EDIT:
A there it is;
curl ``http://remote3-local/api/system/power/battery`` -u web-configurator:PINHERE
It returns;
{“capacity”:97,“status”:“DISCHARGING”,“power_supply”:false}