box spring - what's the point?

[greenelephantscarf]

looking for a new bed as ours finally has given up after 14 years...
most shops have massive and ugly box spring beds instead of proper slatted frames.
what's the point?

Ours is a sprung slatted frame (but we did buy it on eBay). Off to Google what a box spring bed looks like....

they look 'cheap' to me (but are very pricey)
we were hoping to get a naice frame. not a bed that you need a ladder to get on.