> I've always wondered why that behaviour emerged..

Speculating: there may be parallels between this and other fields with entirely unnecessary artistic expression. Think watchmaking where watch movements with superlative finishing are celebrated and often command premium pay (e.g watches with the Geneva Seal). Beyond a certain point, the finishing adds absolutely nothing to the watch aside from showcasing talent.

There's something to the idea that if someone spent a ton of effort building something, even if it's superfluous, it garners a level of trust in the end product.

  >Speculating: