When and why to use Armstrong style tool holders?

[Ultradog MN]

I have right and left hand tool holders that came with my lathe, they’re actually Williams brand though I don’t think that matters. What’s the advantage to using one of these rather then just sticking a piece of hss in the lantern tool post like I’ve been doing?

In my opinion, there is no when or why.
They had their day. They built a nation.
But their day has passed.
Even an indexing four square type is superior to a lamp post type. And a quick change type, better yet.