The OFL is a copyleft license, so while it's a license that is specifically tailored to fonts, it's definitely not similar to releasing a font into the public domain.
A good "public domain" license would allow the licensee to use, study, copy, merge, embed, modify, redistribute, and sell your font without any compensation or obligation to mention your name or obligation to release the derivative work under any specific license, plus the usual warranty disclaimer ("THE FONT SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND," etc).
I still feel that CC0 is the best option if you want nothing from your font or glyph or whatever.
Upright italic/Bulgarian/Latinised forms are perfectly acceptable for logo/signage purposes (not all of them, of course, just m, n, g, ɯ really). You will often see a sign that says "Проgyкmы", or "Деmскuŭ саg".
However, they are practically never used for running text, unless you want to imitate handwriting for some purpose (e.g., to typeset a pre-filled form, "ФАМИЛИЯ: Нuкumuн").