As an artist and designer, I imagine he collects them for the pure joy of being able to admire them, as well as possibility appreciating having access to them for design inspiration. It also sounds like he enjoys collecting pieces that he feels may otherwise disappear. He notes some are not printed on exceptional materials, nor finished beautifully, but he finds the design itself exceptional, and therefore worth preserving.
I realized I wrote the above in such a clumsy way! I meant to say "As he is an artist and designer"...