Yes you need a Google Account from an country where Google Pay for Smartwatches is active. I have one from the US (created with VPN). You can add the second account without removing your normal one.
After that you should be able to activate it.
Your message inspried me
I'm in Hong Kong now, and I have an us google account, both local and US account all added in my LG watch sport google pay
so yesterday I switch google pay to my us account first, then added my previonsly successed VISA card, problem still exist, need to active pay enabler again and again for a while
but when I switch back to my original local google account, and added again for my previonsly used VISA card, problem seems solved!!
now already 24 hours passed, no need to active pay enabler again , google pay doesnt disppear any more
and also made a several transaction successfully.
but the situation is:
I disable my phone to connect my watch through BT , I'm afraid of when watch connect to my phone, the google pay will fail again
now I just connect my watch to WIFI.