It’s all about pressure distribution. Using your shoe laces, you can shift the pressure on feet to different parts of individual foot. This can greatly improve your comfort level. Hope this helps.
An Engineers’ Guide To Shoe Lacing That Will Improve Your Foot Comfort
Is there a way to tie laces to help fallen arches / flat feet?
Not that I know of but you can buy shoes/trainers that have a lace trap that lifts the arch of your foot.