We are physical creatures existing in a physical world. When we connect with other physical things of importance, we resonate with them. They spark a thought, stir an emotion, speak to us a story of our life that has been resting quietly in our memory.
The imperfections of physical things are a feature, not a flaw, in more ways than one. Scuffs, scrapes, and scars add character; a badge of honor for taking hits along life's merry way. For a collector, owning a prized item is one thing, but obtaining a mint condition version in a world of imperfections is a worthy pursuit.
Physical TCG's are objects of human craftsmanship, which naturally come with all the beautiful imperfections of being a physical thing.
Digital items are homogeneous. Always perfectly perfect. To us that is a flaw not a feature.
Collectibility is why we are not making a digital game.