That was their early model. They took money for a product and produced a positive video on it. That was the channel its how it got started and grew. They always used weasel words (still do) like a company "hooked them up" which meant they received a free product and payment to produce this video. They were actually caught properly on this on a series of AMD sponsored videos which were so incredibly positive and glossing over the issues and AMD explained the videos had been paid for. It turned out that was how the channel worked, they got paid for positive reviews.

Nowadays sponsorship is better declared (because the ASA required that of them) but conflicts of interests aren't. There is also the appearance of a lot of fraud too where free products are being placed into their homes. The Intel extreme series is a prime example of something that looks super dodgy and maybe a tax dodge. Right now its hard to prove something criminal is happening, based on their history however its not unreasonable to suspect it is.