What is a key difference between Hofmann rearrangement and Curtius rearrangement?

Curtius rearrangement uses BR2, while Hofmann rearrangement uses azides.

Both rearrangements create isocyanates as intermediates.

Hofmann rearrangement produces esters, while Curtius rearrangement produces ethers.

Hofmann rearrangement involves BR2 and a base, while Curtius rearrangement involves azides and heat.