Not necessarily…

Toast has several features that Burn Disc doesn’t. Burn Disc is handy though, if you know a bit of Applescript you can schedule disc backups or if you just want to dump a bunch of files onto a disc quick and easy. But beware, because discs burned with Burn Disc will only format for Mac OS X, not Windows. A feature worth having Toast around. But if you don’t want to pay for Toast, a freeware app called Burn will get you by.