Liability Clauses in Leases... Meaningless?

[Jon K.]

I have clauses in my lease saying I'm not responsible for injury or loss to person or tenant's property, and that tenant waives all claims.

Are these clauses meaningless?

If something happens, they can still sue, lease clause or not?

Say they fall down the stairs. Or, the pipes freeze and leak all over their stuff. Or, a freak hurricane wipes the place out. Or, something sparks.

Would liability clauses in a lease be useful, or am I kidding myself by even including them in the lease?