For a long time they really didn't need to take it very seriously - there wasn't enough money involved in it that it really mattered to them (from their perspective, who cares if a couple of "nerds" trade a fake currency back and forth between themselves). But now, as both the number of people and the amount of money involved as increased, they've decided that its getting too big to ignore and they need to take it seriously. But there is both good and bad to "seriously" - in some cases, it could mean that they see it as a threat to their own financial systems so they want to ban it, in other cases, they might try to create protective legislation which either A) could help or B)could misunderstand the fundamental idea of a decentralized currency and hurt it. So honestly, its a bit of a mixed bag at this point.