What's Redgate's sales pitch on VDI tools vs VSS tools?

We have licenses of SQL Backup for a few of our SQL Servers. I love the product and what it does for us. We changed MSPs, and the new MSP uses StorageCraft (ShadowProtect) agents on all our servers for backups. We're not seeing eye to eye on having them disable VSS on our SQL Servers, which breaks our SB backup chains when it performs its VSS backup(s).

I think they finally understand why we can't use both at the same time (broken backup chains). I'm still having a hard time explaining to them (and my boss) why VDI tools like SB are better than VSS tools. They argue they can restore our databases to point in time (I'm skeptical, given our past troubles with Veeam and it's non-VSS file system backup problems). I say StorageCraft's use of VSS is a black box, with not enough visibility into and granular control over backups and restores, and while SB is also a black box, it's less black for those same reasons. :-)

What is Redgate's company line...sales pitch...to a company weighing a VSS-based SQL Server backup solution vs. a VDI/file-based solution like SQL Backup? Please help me convince my boss (and these MSP folks).

Thanks!