Short answer: No, its not necessary, the creators posted that before even the Basic version was released.
Opinionated answer: Not if you dont want to enjoy all the information to be jammed in there. Magic items alone are good enough for me, the possibilities of certain "Evil" character types (BlackGuard Class, Death Domain, etc..) sounds wonderful. Tons of ideas on how to build encounters/campaigns, sure I've DM'd enough that I can do without but you never know what kind of new ideas might be within. Then we have alternative "House Rules" that should be an interesting read with Firearms, explosives, and alien weapons as Icing on the cake.
Opinionated answer: Not if you dont want to enjoy all the information to be jammed in there. Magic items alone are good enough for me, the possibilities of certain "Evil" character types (BlackGuard Class, Death Domain, etc..) sounds wonderful. Tons of ideas on how to build encounters/campaigns, sure I've DM'd enough that I can do without but you never know what kind of new ideas might be within. Then we have alternative "House Rules" that should be an interesting read with Firearms, explosives, and alien weapons as Icing on the cake.