Optix Denoiser should absolutely keep the same privileges as native denoiser. Use in any mode (Interactive or final).
Given that denoising is now possible during interactive, there should also be the same behavior as during final one, being able to blend on scale 0-1, very useful for both finding good compromise between light clarity and material detail while also enabling to turn it "off" sort of.
Give it a rollout or parenthesis description of "preview/low quality" if you must, no issue with that, but definitely keep them at same level of flexibility.
It is the best feature in long time and imho should deserve forefront attention. Absolute revolution for me.
Regarding it, do you guys feel like it works less once the rendering reaches certain amount of passes or time ? My GPU will spike to 100perc. during intitial denoisings, but then hover down.