Ehh, decent services for earning some extra sats, but I'd guess that these services are a nightmare in terms of privacy. They're businesses and they'd need to earn money one way or another, and I'm betting that it's through gathering of data.
Definitely they are farming information for sale on you later on, this shit is rampant currently and only getting worse unfortunately.That's because we, the people love to save on and we don't think much about privacy when it comes to fiat but hey, you get freaked down all over once you have that BTC on your address and voila, this gives info to the advertisers that you are now a proud owner of some Satoshis (a smallest unit of BTC). However, I saw Amazon.com in the first image and I'd like to say that Amazon gift cards allow you to add money and pay for almost all types of services these apps are making available to you, so why not do a flip of the services and instead trying to catch on some Satoshis via these sites and break our privacy, just visit Localbitcoins or paxful, buy some BTC with your fiat and then let others buy your BTC against Amazon gift card for around 40-50% higher payments per BTC? I'm sure there are dealers who do like that and save a lot of bucks while paying for their bills (and maybe their neighbor's too)
I know I didn't talk any shit about cashbacks here but this 40-50% discounted purchase of AGC without having to reveal your identity is much better than going for some Satoshis while giving all your data on these websites. I know that purchasing BTC on exchanges also need kyc to be done but that's the minimum kyc they ask for, while on the other side the exchange won't know where did you use that gift card, so you are safe on one side at least. 
