There is a measure of self-serving here, to be sure. But there's also a major point often ignored by people who emphasize technology over sociology - money, and economics in general, is a social thing. It's not the technology, the technology is a tool, the society, the decisions taken by people and their interaction is what makes economy. And laws is the distillation of what society thinks about it.
Surely, new technologies influence decisions, and enable new ways of interaction, and laws can be outdated. But ignoring that sphere altogether and claiming since we've got new technology old laws of how money works does not apply anymore is dangerous. A lot of it still does apply. If we ignore that, we get what happened at dotcom boom and then crash - people claimed old rules of economics, supply and demand, scarcity, etc. do not apply anymore - turns out they largely still do.
Yes, we've got some new ways to do things, but fundamentally it's still the same story. And it seems to be, the same story with Bitcoin - money do need legal support. Some people - mostly those who live outside the mainstream community - can be ok without it, but vast majority would not be.