In theory it should not matter to Pega whether you use secure files or basic files for your blob storage. However, we have seen issues with secure files, especially in versions of Oracle prior to 184.108.40.206. Please see this article for some recommendations when using secure files. You can also google this high number of busy waits related to secure files to see more details of the issue symptons.
This request is yet to be reviewed by the Pega Product Management team. I recommend that you check with your Account Executive by referencing the number stated in the Related Support Case Number field above.