People love the way it looks because there is an incredible amount of artistry in everything. The armour and weapons are gorgeous. The architecture is inspiring or ominous in turns. The monsters are excellent and the bosses. Oh the bosses.
There is a big difference between rendering horsepower and beautiful design. Souls games are decent with the former and brilliant with the later. That's why people say they love the way it looks.
Yeah if you play DS1 on PC with DSfix at a good resolution, you can really see the work put into the armours, weapons and enemies.