I mostly use echo to control lights and other things that need to happen very quickly. The button is a backup plan for something, particularly if for whatever reason I want something done quietly. Or if the room is so noisy that echo can’t hear. Or if it’s one of those days when my own voice is very slurred, which happens sometimes.
Right now, the plan for the first button is just to turn the entertainment center on and off. So it doesn’t have to be as quick as a light would be. I’m getting a pretty consistent eight second response time from the flic via IFTTT which is just fine for this.
The yellow button on the left side of the entertainment center is a flic. I can push it with my knee from the wheelchair and the dog can push it with his nose. 
I also plan to eventually have a flic that will activate an automatic door opener.
As far as the HTTP method, sure, that should work. That’s how Dave glass originally set up IBeacons/SmartThings integration.