Samsung seems to believe foldable phones are the future; however, that future has come with the potential disadvantage of cases that come in 2 parts and do not cover their hinges. However, Speck has addressed this issue with its new Presidio Perfect-Clear Fold line for the Galaxy Z Fold3 and Flip3.
https://www.notebookcheck.net/Speck-announces-Presidio-Perfect-Clear-Fold-cases-for-the-Galaxy-Z-Flip3-and-Fold3.555473.0.html