I am currently using 43GB out of 128GB on my device do I need iCloud storage?

That depends. No matter how much storage you are using on your device (or how much you have free on your device), If you want to do iCloud Backups, sync Photos to iCloud Photos, or sync any other data to iCloud, you would need at least some iCloud space to do that. How much space depends on how much you want to sync. You get 5GB of iCloud storage free and for me that is enough for iCloud Backup and to sync my Contacts, Notes, iCloud Photos. For other people, especially if they have a lot of videos, they would need to upgrade to a larger iCloud storage plan.