I heard somehwere that when you become rich, you buy a yacht. Not because you like them, but because they do nothing but cost ridiculous money, and to have one shows everyone how much money you have to waste. The bigger the yacht, the bigger the pile of cash you are throwing away.
With the insanely rich, the ultimate expression of wealth is not a yacht, or even a fleet of very big yachts, but a Premier league team, by owning one you are expressing how disgustingly rich you are by being able to waste so much cash.
(Of course you could also be laundering drug money, raising you public profile to make any assassination attempt much more expensive, or have recently been deposed as Prime Minister of your impoverished Nation, by their Army and wish to clean all the money you stole from said impoverished Nations public finances through a football club)