Yes...you can leave them. I have them too & they run fine. I assume they're "periodic" mode jobs? That mode turned into "Legacy" in v12. If you decide you want to update them though, you can start here in the Guide on how to do so. 

We have them as well and I have followed the link Shane posted to upgrade as it requires backup chain format upgrade first before you can change the job.

You can keep them until you upgrade the backup chains. The legacy backup copy jobs won’t work after you upgrade backup chains. You need to create new backup copy jobs after upgrading backup chains. The new backup copy job supports changing Copy modes (Immediate copy and Periodic copy).

2 main differences I think with the new copy job : they are true per-VM (a metadata file per VM instead of 1 metadata file per job) and you can change between immediate or periodic now what was not possible before.

you can keep it if you want, but the new layout is functioning better than before