Bart,

I know that topping lift can be a PITA but it still has a lot of
advantages over the rigid vang. Just to mention a few;

A spare and ready back stay

A man overboard hoist

An end reinforcement of the boom when you want to use it as a crane
(Dingy recovery)

Ole Thom
P/S I've used to tail as a temporary sheet while clearing an over-ride
on the main sheet wench