Yes. I am asking exactly that objective question.
They are advantageous to leverage in certain situations but essential they are not. We're used to, in the technology industry, looking for or creating problems to solve with services we are aware of. Moving back to necessity and need, do we really? Are we being objective? Most of the time, no.
DDoS protection is pretty essential. I highly encourage you to read through what they offer if you're not familiar.
Theres a few alternatives, but at a minimum yes you probably need their or a competitor's Name Servers and their public DNS. Rolling your own isn't very feasible.