Bitcoin was not created to confront or challenge the monetary system, it was created to be an alternative, but that goal has also failed as it is only used as a speculative asset these days.
Bitcoin is a speculative asset like stocks, or some people use it as a store of value like gold, so how can it challenge the global monetary system? Bitcoin will not change or affect the current monetary system, nor will the fiat currency system face any problems just because of the existence of bitcoin.
People turn to bitcoin simply because it is a potential asset and has the opportunity to bring higher returns than traditional investment assets such as stocks, gold, real estate.
Something that was created to be an alternative can be a challenge to others if people find it more better than what has been the traditional thing. I can comfortably send someone in other part of the world Bitcoin right now and they can receive it under some minutes, sell it for cash without raising a voice but if you want to do wire transfer today, it might take 3-7 days before the recipient will see access to that money, now tell me why banks wouldn't envy Bitcoin.
Bitcoin is what we should have had from beginning before all this fiat system that is controlled by the government, Bitcoin doesn't have anyone who control it. Do you know that today if government want to have Bitcoin as official and regulate it to their own taste, they can do it and even minimize somethings they fear about like money laundering and the rest. It will even be better than the fiat system they think is better than Bitcoin they talk about all the time.