They are in deed but usually with some commentary and with an alternate “short” ending. Hence the question when Mark, chapter 16 beyond verse 8 is quoted.
It’s not a personal challenge but I think a legitimate question when these verses are quoted, particularly since there is the real possibility that these verses are not original to Mark.
Those verses really don’t say much that you can’t find elsewhere in Scripture anyway.
If it came down to a need for Scriptural support for something, I’d probably pick those other verses which address the topic and are less likely to be challenged on their authenticity.
That said, I still find it hypocritical and disingenuous for people to cherry pick a verse as to what to believe within a verse. Like, someone will use it to support the need or requirement for water baptism but laugh at the speaking in tongues, healing the sick, drinking poison, and handling snakes.
People ought to at least be consistent. If Jesus said one part of the verse, He said it all. If you’re going to believe the necessity of water baptism on that verse, then believe the rest.
If you’re going to mock and discount the tongues, healing, snake handling, and drinking deadly things part, then don’t use it as a proof text to support a requirement of water baptism for salvation.
That’s what gives me the most trouble when people use that passage; the cherry picking.