It’s usable. Provided you have a 128 GB OG SE.
64 GB of storage is horrendous in 2023. People will say that you don’t need that much storage but these folks are all foolish. A simple app like Gmail is like 455 MB big now. Twitter is like 300 MB or something. Now if you have all essential apps and maybe one or two games installed, you’re almost at 35-40 GB used already.
With the 128 GB, you don’t have to worry about the storage too much for daily apps. Next will be the battery life. If the battery was recently replaced, you’re good.
Also being on the latest iOS version will guarantee you that you will have the most recent apps that can still be installed today.