What are the advantages/ disadvantages of having lined climbing shoes? And also what is webbing used for?

This is the difference between the types of shoes:

Lined: these shoes will not stretch as u wear them so they need to fit correctly when u buy them. Since they only mold the shape & wo not get bigger, they will keep a truer size & wo not get sloppy. They r also easily cleaned inside with a brush & some soapy water.

Unlined: these shoes will stretch & even if too tight when new they may get more comfortable as u wear them. Many have a ''slingshot rand'' which is stretchy rubber that goes from the toe to the heal which keeps the toes very tight - even when the leather stretches. These form to ur feet better & r often more comfortable but do not have as much structure & can get smelly - the leather inside is hard to clean.

I've had both kinds & prefer lined for all day Trad routes & unlined for hard short routes & indoor climbing.

Good Luck