What is there to be optimistic about?
There has been no explanation from Monarch or the CAA about these chartered in aircraft so I'll make my own assumptions
The company is currently going through an emergency fundraising round
It was apparently in talks with the CAA on a Sunday night (didn't know the CAA worked Sundays!)
The information available is extremely limited, except twitter which says there's nothing to worry about so we can all relax
I take no comfort from them being backed by Greybull, because they'll do and have done what their spreadsheet tells them is the best answer
If you book a flight - i.e. deposit money in the company's bank account - you're apparently fine because of ATOL or maybe your credit card protection.
Won't the credit card companies now want greater funding/guarantees? Will they refund the rest of the cost of the holiday? I've no idea, but I can't see the benefit of incurring time and expenses to find out when you could just book with BA/EZY/RYR etc.
I think you'd be nuts to do business with these guys unless it's mega cheap.