The difference in the cost of most bullets today is not all that great in my mind. Swifts can cost $1 each, standard cup/core about $0.35 each. In theory, the Swift is 3x as much - but given a reasonably accurate rifle/scope combo, a decent load can be found with 100 bullets. So the total cost ranges from ~ $45 for cup/core (including primer/powder) to $115 for Swift. In my mind, that isn't a deciding factor. I spend $600 to $1300 (my favorite - WY "Special" NR elk tag) on my elk tag every year. I'm in my $300 boots, using my NF scoped Kimber Montana, hauling my $900 Kifaru pack. And that doesn't count the other "necessities" in the pack.
The deciding factor for me is the purpose of the bullet in relation to the animal, ranges I'm hunting, and bullet launcher. For elk, I've used everything from a Sierra Game King to the Nosler Partition. When I'm shooting a bullet launcher that launches them 3000 ft/sec and expect elk to show up at 50 yards, I'll default to a bullet that stays together. When I'm dragging my 308, some standard cup/core work just as well.
Short answer: No they aren't required.
Caveat: bullets are the cheapest part of the equation, why pick a bullet based on price? I'll pick them based on intended purpose.
