Why some gpt sites ask for verification?

[Icydoll]

Joining on gpt sites is quite easy to make money but most of the sites ask to provide more details and ask to provide proof ID . We are already giving our profile information while filling up the surveys. After earning certain amount from the gpt site they ask for verification to get paid . Onedayrewards.com is one such site . There are reputed website like toluna where they never ask about verification proof ID .

There are people never mind to join such sites. Im not interested in joining such sites . It's better to join reputed panels than gpt sites .