Is Vitalchek legit?

I think I saw someone post about it the other day but I couldn't find if the birth certificate they send you is a certified one that I can use for legal purposes. A few online sources claim that you can't, but it's on the state's website. I lost my binder that had it and a few other things in a move so I'm trying to get this figured out while I have time. I wish I could go in person to replace it but I don't live in the state I was born in. I tried calling the office in my birth state but didn't get an answer, even though I'm pretty sure I adjusted for time zones.