The role of a content creator is to promote the game for other users. This is why Hell Hades and other content creators get free gifts for their main account. They can use it to max out champions and builds, and build proper content.
It's also worth noting that Hell Hades spends thousands of dollars a month with Raid as it is his primary source of income, so it's not like he is just getting things for free without doing anything. The free content creator rewards are an additional perk.
The free rewards like this only apply to a single account which is their main, and usually CC's have multiple accounts. The other accounts do not get any such reward and for some creators they use this to further demonstrate the game and take new players through a similar journey of starting off with nothing. This includes things like selecting champions, teams, builds, etc. These additional accounts are usually Free to Play, or even low spend. You can view HH's one at https://www.youtube.com/watch?v=iuAngaRwbkI&list=PLUIeSAUVoCqLKkjY90KksbGMFD-wndDC2 to see what I mean.
Finally, I think it's worth pointing out that other people getting free items doesn't really affect each of us as a player. We are all tackling content at our own pace and level, even things like Arena. People like HH getting free chickens every now and then doesn't mean you are in a worse place
Edit: While I think of it, these "free" items aren't actually limited to people like Hell Hades. Anyone can get them, as long as they put in the effort. All you need to do is spend something like 6 hours a day for the first 6 months compiling and editing content, then maintaining a youtube channel, and then get recognized by Plarium. If you really want these free chickens then the only thing stopping you is yourself!
