Credits may not come as easy elsewhere (GB for the OP, D for me) as in the USA and CDN. These are priviledged markets IMO.
I tried the video thing - very boring and low money. I tried the survey thing - scarcely an offer, and they may promise 45 crs for which you are not eligible after some mins of pre-interview. The "best" survey I completed was 27 crs IIRC - a petty income.
Offers must fit and often only give 20 % of the costs - hardly a deal.
After all of that, I've given up on "free" credits because the price is too high, payed in terms of my precious time. OTOH, I see the fun I have here and I'm ready to spend a dime. 1000 cr per month for budget balls, a few green fees for the truegolf courses.
WGT sure ain't a site to make a fortune, the return in real value (Amazon gift cards) is meagre, 300.000 crs for 500$, that's a rate of 1:6.
The "best" offer is 10M crs, a trip to the past US Open at Congressional - a budget time trip, don't you think?