If you only do "full" backup that include Data Dir it should be OK but Snap Creator do a CNTRL file backup also when you backup Archivelog only and in that case if you put it in your Oracle Data directory you will not get that istance_preBackup_trace file backed up.
You can also put the backup controlfile for full backup in data directory and the one done with archivelog backup in archive directory.
Regards
Francesco