It is not necessary to use maps. Many thru-hikers skip the expense, weight and hassle of keeping up with them. You can follow quite well with either the Companion or AWOL. They have a map. Maps can be helpful if you get off trail and can give you egress help if you need to bail off trail. They can also help find water. Some of the maps are downright worthless because they are outdated. The ATC and trail clubs push them because they are a big money maker. Today with an I-phone and the guide, it's not needed. You will also hike with others who will have maps to look at. The maps are quite a mess with dozens of formats, legonds, scales, colors. One will be good for 2 days the next is good for a week. It can be aggrivating.
_Francis_