unfortunately it all depends on task and who put it up, which you have no way of knowing, I've seen more then a few for apps take you to a site that tries to steal login info or tries to get you to download some virus. *shrugs* some pay out, some don't.
I completed a task from lords mobile and got 2250 gems immediately! So it's working for me.
in 3 steps
Choose the game that interests you and play itfor free.
Every game has some quests for which you will receive Soul Gems.
You can exchange your Soul Gems for Steam Wallet top-ups, game keys, CS:GO Skins and other rewards.
You know that on Gamehag you can get real rewards for free, right? Join us, complete walkthrough and get your chest!
Wanna try some task on mobile device but wonder if it really gives reward