Why are caves important to humans?

In prehistoric times habitable caves offered shelter to people living in their vicinity.

Various caves have had various uses down the centuries - the huge entrance hall of Peak Cavern in Derbyshire's Peak District (UK) once held rope-walks, and shows one today, though I don't know if it's original or a replica. The show-cave section of Wookey Hole (Somerset, SW England) has an artificial exit tunnel that both leads tourists back out to the sunshine - and other parts of the tourist site overall - and is used for curing cheeses!

Active caves are conduits feeding water from the hills to springs, so sources of water (though this is also true of aquifers of course).

Nowadays show-caves are tourist attractions, so contribute to their lcoal economies as well as showing non-cavers what caves are like.

Generally caves are the venue for the pursuit of caving, an activity that combines physical and mental challenges with particular aesthetic attractions not found on the surface; and to the dedicated cave explorer the chance of discovering "new" caves or series - places no-one else has ever seen.

This in turn supports businesses supplying equipment, publications etc, and of course cavers visiting caving areas spend money in local shops, pubs, cafes etc. In the UK at least many caving clubs own "huts" - rather more palatial than that suggests - self-catering club-houses that contribute locally through rates and often use of local suppliers of requisites like building and cleaning materials.

Caves are also of considerable scientific interest and significance under the umbrella title of Speleology, covering principally geology, hydrology, Biology and Archaeology. At present a good deal of research is into geological evidence preserved by being in caves, of past climates, helping us to understand climate change. The formal reports are generally published in learned journals like Cave & Karst Science.