What do you use for ”area terrain”?

What do you use for area terrain? Something the models actually can stand upon to get cover? The rules suggest hills or stormvault.

Are the Old world warhammer hills from GW suitable or are they to big?

https://www.warhammer.com/en-SE/shop/the-old-world-warhammer-hills-2024

If I make my own hills it will probably look bad and the warhammer hills are reasonable priced imo.