The concerning thing is that with that type of constant backing up if some malware (and I'm very general when I talk about malware) gets in and you have backups that quick, it can very well affect backups as well.
I personally wouldn't have a NAS (and I don't) with that quick of a backing up schema. Mainly because it means a perpetual online connection (vector for bad things to happen) with a redundant back up that's that quick, good chance (depending on what that malware is) that it could affect that backups as well. All my NAS backups (while they do for time use the WAN) are just long enough for the back up and I do have scripts that very day/time as well.
I have instant backup. But it's not my only backup.
I admit I do raid 0, which scares some people But raid 5 takes too long to recover from, and I do similiar to raid 1.. just with another device.
I have 2x 8 TB on a Nas, and everyone stores their files there. The moment a file gets saved... It gets uploaded to Google drive, and blackblaze(both encrypted) , as well as to my home from server via FTP with write, but not rewrite access. So they have to hack my PC, our work server, get the password to two clouds... And break in and destroy our external.
Ontop of that... I have a snapshot of all previous years files saved in multiple places, and the current year gets snapshotted every 2 weeks.... All saved to the usual places as well as an external, offline drive every month. So if someone does manage to delete or corrupt everything on both nas, ftp and 2 clouds... I just recover the snapshot and lose at most 2 weeks of data.
I feel like it's overkill. But our IT company wanted $200 per TB for backup... We were paying $600 per month, and they wanted to increase it to $800. Once I found that out... I told them how ridiculous It is considering they just off-site backup to a local data center.
Now we pay $15 for gdrive per month... Blackblaze is $10 I think? I have 100+TB at home so I just do that for free. It cost me $1500 to buy 2 really decent Nas with 16 TB each. So it took two months to break even... And now we're saving $775 per month, and aside from the external drive every month... Everything is automated. I login once in awhile just to make sure everything's working ok, but that's it.
There's better, more fool proof ways. But realistically... Were a sign shop. Odds of anyone trying to access our data are slim to none... And the protections in place are more than enough security level wise for what we do.
I think realtime.backup is great... Providing you have contingency plans.