NOTICE : YOU DO NOT OWN GAMES PURCHASED FROM STEAM' STORE (You can find such statement within steam's EULA).
You will rent everything, pay money for subscriptions, own nothing and be happy [agenda 2030].

Always remember you are LEASING products from steam' store (What you are purchasing is the the product's license to USE, Instead of doing so; Encourage the developers to support 3rd party stores with no leasing nor DRM.

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STEAM CAN ALSO ACT AS A MALWARE VECTOR

(see the case of street fighter 5, a rootkit added in one of the game's updates called capcom.sys that could allow attackers have full access to the infected PC)
Steam allows the removed / update / adding and executing programs on your machine which means that it can do anything valve or other developers want (Preventing updates can make the game unplayable, only starting the client offline may help), this isn't in theory, it was already done (see example above), avoid steam like the plague.

In the meantime, Piracy is also an alternative (But note that binary products like games .EXE and .DLL contain viruses on piracy)
(If you decide to risk it, Please send a cheque to the developer's PO box afterward for the total amount of the product, We are not disgusting soulless commies after all)