my opinion...
No one "NEEDS A CUSTOM", just like no one needs heated seats in their vehicles, but they sure are nice!
I have seen people compete with bear bows and win. Heck, I even know a guy who won the Howard Hill with a bow he built that is flat out "junk". The limbs aren't perfectly square to the riser, aren't tillered perfectly, etc, but man, do I shoot the bow well!
It's really all about what you want! Don't worry about "needing" something unless you're very frugal, which is fine! But, sometimes it's nice to have a custom.