Is it safe to change the Recovery Model of SSRS database ReportServer to SIMPLE? I'm changing the recovery model of ReportServer database from FULL to SIMPLE.

Is there any reason why i would not want to do this? Besides the obvious answer of losing point-in-time recovery? (i am not doing transaction log backups on this database anyways.)
If you're not using transaction log backups, then you don't need FULL recovery mode. It's that simple.