It's lame that Blackflame keystone says Fire damage from Fire Spells

Why is it so restrictive? Why not allow chaos skills to ignite? I doubt it would even be worth mentioning compared to Flameblast, and as a result, it is just lame and I'm making this post.

Chaos skills are even giga early in development (copied poe1, so could be adapted) and most suck for igniting (so not very dangerous territory).