They control their cash and assets. This indicates that investors believe Zynga will use up their assets without producing any profit from them—that is, their RoE is negative.

You would be paying less than book value (value of copmany divided by number of shares), true.

However, if they lose money, then the book value will drop some more. Only if the company failed utterly and then returned the money to the shareholders (not likely) would it be "safe" to focus on book value.