Oh I agree completely. I am not sure if I have ever had it work. But it is only 1 point for an extra health and it will kick in occasionally. Looking at the other 1 point astromechs, I am not sure there is anything better.
You could make a good case for R2-D6 with adapability so you can play Zombie Biggs against Brobots or Crack Swarms. But unless you are facing lots of opponents at PS4 or PS6, it won't work at all. R2 Astromech is OK and may help with shifting stress if you have to K-turn in order to keep up with more agile wingmen but does not directly boost survivability.
I feel that R4-D6 is probably the most useful 1 point Astromech for Biggs. If you want something that provides better defense then you have to spend more points. Personally I would rather spend the points on the rest of my squad but if you find that buffing Biggs further works for you then that is cool.