Physical Vs Logical delete of file stored as BLOB from Database

I have app in grails(uses GORM - grails ORM) and DB is MySql. I have table called 'attachment' in database which stores the files attached in web app as blob type. Each file size varies from 30 kb - 200 kb. Now I want to provide a provision for users to delete the attachments. The entries deleted will not be re-used and i don't have unique constraint on any fields.

total size of table attachment is 35 MB. Which keeps growing.

And there is a relationship between the table 'attachment' and table 'training'. which says training has got many attachments.

1) Is it good idea to use logical delete (deleted = true) against the physical delete ?.

2) Does logical delete affects the performance of DB (keeping the rows in the table without deleting them) ?.