If you squint, you can see why someone might think they were a good idea, but with a closer look the web of logic tears apart.
Let’s have a look at an Alpha Bee. According to the json it weighs 815kg. Let’s say a meaningful contribution from lighter than air gas sacs would be 10%.
X - X/10 = 815
9X/10 = 815
X = 815 * 10 / 9
So it actually weighs 906kg - 91kg of ‘uplift’ provided by the gas sacs.
How much volume would that be? I’m going to assume they are using Hydrogen (should really be more explosions, but it’s lighter than helium).
This site Helium Balloons Calculator (it does also do hydrogen despite the name) suggests that that would require 80 cubic meters of hydrogen gas. That’s 80,000 Litres. However the Alpha Bee itself is only 625 Litres.
Conclusion: Either the Alpha Bee is a TARDIS, or the ‘gas sacs’ don’t do crap.