Embedded SQL in OPM Cobol

We are mainly an OPM COBOL, CL, DDS file structure shop. Most of our code
is normal I/O. I have no problem using the normal I/O in OPM Cobol, but
have thought about start using more embedded SQL. If we don't change to
DDL file sructure (which I doubt will happen any time soon) is it of any
processing benefit to use embedded SQL in OPM Cobol? If I am making a
change to an OPM Cobol program and it is full of normal I/O, can I add
routines to read, update, delete to those files in embedded SQL without
changing all the other normal I/O routines to SQL? Say the program is
doing normal I/O on a file and I add a routine to use SQL to access it but
leave the normal I/O routine running also, any issue with that?

Thanks,
Jeff