Can you use a guitar rack stand instead of putting your guitars in their cases?

I was thinking of getting the Yorkville Sound
5-7 Guitar Side Loading Folding Touring Stand and use that for now on instead of cases.

I know it's not going to protect my guitars like the cases but I find it more convenient.

Is this a trick question?

If you want to actually play your guitars then you should absolutely use rack stands, that way if inspiration strikes you can just grab the appropriate tool.

Cases are for transporting guitars safely from one place to another.

Also do hard cases protect your guitar from humidity or dryness?

I mean from humidity and dryness.

Are we talking about acoustic guitars then?

Nope.

Both Electric and Acoustic.

Unless the case is hermetically sealed, no.

Extremes of temperature affect electrics, acoustics are more sensitive, if you live in a very dry climate you should humidify your acoustics internally when stored.

A "good" hard shell case makes the task of keeping your guitar properly humidified worth the effort.