IsDate() silliness

https://connect.microsoft.com/VisualStudio/feedback/ViewFeedback.aspx?FeedbackID=219046

For the life of me, I cannot understand why Microsoft would change the behavior of a function that has been in place for X years.

Does allowing date values with a decimal separator make any sense to anyone out there?

I only stumbled on this because a corporate expeditor was searching for a voucher whose value was $819.03. If the value had been, let's say, $1600.46, it wouldn't have been an issue.