I assume you mean for DB2 for OS/390. No, IMO it is not particularly good and serves no real purpose.
On-line transactions (CICS) have to be in the same plan to allow use of transfer control from one transaction to another. In CICS (at least the last time I worked with it) a CICS Start transaction is required to switch plans, which is not an ideal situation since it is more efficient to transfer control and not do a Start. This was the reason that packages were developed in version 3.1.
One can use packages in batch, but the only reason they were created is to support CICS.