It's only serious if they don't recognize and rectify the problem quickly. If they fix the problem and make good with customers that were hurt by this then I think it could work out better for them. This gives them a chance to demonstrate that they take care of their customers. If handled correctly this issue could instill more confidence.
Although they could fuck this up royally and hurt the price of Bitcoin globally.
What a pain in the azz it would be to have to go thru the linking process for a transaction then delete the link every time.
I extend faith that they will resolve this ASAP>