pad / sheets etc - fitted or not ?

for example this one is fitted:

and this one is not:

otherwise the two are similar, except the non-fitted one has feedback on it.

i have an idea of what the cons / pros are but as i was born in Soviet Union i have never actually used fitted anything so my ideas here are purely speculative.

it would appear that fitted sheets will sit flatter but not feel as soft due to being somewhat stretched ?

what do you say ?

do you know any other cotton mattress pads that are similar to these two and worth checking out ?