Author misinterpreted specs...

"Each packet has 20 bytes of useful payload and consumes 49 μA at 3 V"

That is a manufacture average for some profile, mostly sleeping 99% of the time.

The real consumption during broadcast is in the order of 15-20mA for most chip I have seen.

Here is a very informative article dealing with power demands of low power devices: www.ganssle.com/reports/ultra-low-power-design.html