That is a fair observation... I'd certainly be happy to allow completing a pickup action to ~99% even when you're full. But I feel allowing actually picking items up when you're full would cause people to accidentally pick things up without realising they're full.
I suppose if it was REALLY wanted then I'd consider adding a button which lets you consume an item early, so long as you have space for at least 90% of it or something? Maybe have a toggle option to automatically do it when you're trying to pick up another of that item? I'll add it to the 'maybe' list for v0.2, but it may be up being pushed back to a later version depending how long things take. I'm going to try and stick to a similar schedule of working on major updates for ~2 weeks then release it, rather than end up feature creeping.