Things like verify in other tape backup software? And direct (VM) to tape backups? And eject the tape after any activity (erase, catalog, etc.) because it's best practice not to leave a tape in a drive?
Advantages to using File to Tape instead of Backup to Tape? First and foremost to me is pulling our backups from a dedupe device. Counter-intuitively, Backup to Tape doesn't just copy a backup file (vbk, vib, etc.) to tape, for whatever reason VBR does some transformation on the files that for us, reside on dedupe device. Opening and working w/ files on a dedupe device is a no-go, please. So we have to use File to Tape to simply copy our Backups to Tape.
To Didi7's point, as much as I've loved and respected Veeam's general VMware backup capabilities, I can completely and identify w/ the fatigue setting in where we're all begging and clawing and prying to get Veeam to introduce long standing tried and true features into its Tape support. It becomes very difficult over time as paying customers to fight the fight of please just introduce this one little feature that we legitimately need and exists in every other tape software (so it would be understood to be seen as a useful feature) and the push-back we get is "Why? What good would that do you? Who would want to do that?" Ending w/ "Well we don't see how that would be useful, so we're going to do it, at least not right now." It makes it very difficult to take our eyes off our old tape software that have been doing the things we need quite well for a very long time. W/ utmost love and respect Veeam, please stop pushing back, take a good look at veteran tape software, and help accommodate what your paying customers are clamoring for rather than insisting on doing it your way. Please.
I don't think any of us are trying to be a butt here (I'm not!), we're just trying to get common features finally added in, and at that are very grateful we have a voice here.