Not only does instructing improve your flying skills (hopefully) it also improves your people skills. There is nothing quite like teaching at the flying club/school level to meet such a diverse group of students who wish to learn to fly for a myriad of different reasons.
Flying instruction is not for everyong but you also have an "end product". There is nothing quite like seeing a student progress from fledging pilot to competent PPL etc. , especially when they have had certain challenges to overcome on the way and you have perhaps facilitated them to be successful.
Everyone remembers their basic flying training (mine was over 30 years ago and I can recall my first solo like yesterday) and also their flying instructor for better or worse!
Yes the pay and conditions are not too good unless you go to the commercial schools but there is much job satisfaction to be had and although the hours can be long they are not nearly as anti-social as other sectors of the aviation business.