i have already tried survey site like yours but its good thing you use bitcoin as payment.
just be aware of some people that use VPN or proxies to get more offer for site like that. as far as i know they can change their country to get more offers if their country did'nt support for the surveys. for me it might be a fraudulent ways.

nice with new way to earn bitcoin by filling survey,
but is all survey are depend on our country? can you add more way to earn? like watching video or maybe twitting service

I'm a US user and I looked at the Adworkmedia surveys; they seem a bit sketchy, honestly. Mostly the generic "$100,000 Sweepstake prize! Enter to get 1500 bits!" surveys that never really pay out. I mean, I suppose it's a decent amount of money being paid out by them, but has anyone actually completed a survey that has a large payout?