@Kwangwon Yi​ Instead of performance, main issue with managed table is whenever you delete table, data under that table gets deleted.

If you have good use case on Reporting, best approach is to go with external storage location to store your managed table data, in that way your table metadata resides on /user/hive/warehouse, where your data resides on some external location which you can access by using /mnt/<xxxx>

we have a new option called Unity catalog, where you can store your managed table and data in your own storage that is best option to overcome performance and governance.