Well, it's still more battery life than a small battery that never charges to 100%, right? I think regardless of the battery size, you can make the decision to preserve the long-term life of your battery or have the extra capacity in the short-term.
Plus, charging from 20 to 80% is much faster than charging from 20 to 100% (I estimate that about half of the time is spent just going from 80 to 100).