"I can just upgrade my GPU whenever I want!"

Not even close.  The included power supply is only capable of providing 180W.  Keep in mind that is the total power which can be supplied to the entire system.  Decent graphics cards tend to use 150-300W power.  

Additionally, the case of that PC is actually quite small.  You won't be able to install a large graphics card even if you want to.  

This is why myself and others sound like a broken record when we tell people "build it yourself, do not buy pre-built".  

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