Also as a note, what's on the Nevernever tends to mirror or at least be related to what's in the real world in the same place. Harry, for instance, has been warned against going into the Nevernever from anywhere on his private evil island lair. If you try to escape a villain's torture chamber, you might well be dropping yourself into someplace worse. You could try to use it as a quick escape and find out you just jumped into a domain filled with acid mists.
Or you could jump in, move a handful of yards, jump out again and find yourself half-way across the world with no reliable way back. Or jump in, stay five minutes, and find out a month has passed in the real world.
The Nevernever is filled with all kinds of fae and other creatures who would love to pounce on and consume an unwitting practitioner. The most prominent Nevernever traveler we've heard of in canon has the title "La Fay" at least partly because "Fay" means "crazy," as in, "You're exploring the Nevernever? You're freaking crazy."
So it can be handy, but know that you're really rolling the dice if you hop into the Nevernever blind.
Wards can more or less block whatever the practitioner creating them intends them to, given enough time, power and resources.