The thing is transferring money with guarantees is a solved problem. All you need is banks and laws and judges and police. We have those. Also transferring funds isn't enough to make a viable currency, it has to also act as a store of value.
Also, I think instead of "solved problem" you mean "solved for white people in rich countries"
Wow that's all? Seems so much easier than just having a crypto wallet and sending anything to anyone at any time.