ya know. data recovery is difficult enough unless you're the NSA, so all the DoD and other highly secure methods of data removal in my opinion are for paranoids and international spies.
that being said more than a format is required for sure and data should be at least overwritten with zeros by a HDD diagnostic like WD DLT at a bare minimum. I used to have an app that overwrote data 9 times, replacing existing files with garbage data, then deleting them and filling the disk with garbage data 9 times. I would use it before writing zeros to the disk with the mfgr's utility (I lost the app and code somehow, but easy enough to duplicate, I originally did it with a batch file.) For the extra paranoid yes smashing the platters when you're done is a good measure.
I just liked doing things my own way, but for most purposes I think DBAN if I recall yes is more than capable. I say if someone is willing and capable of going to the measures it takes to recover your data after that, then more than likely they don't need to recover your data, they've already found another way to get at your info and it's a moot point.
now for all intents and purposes of the elderly and non-computer savvy, taking computer repair techs/services completely out of the picture as if they didn't exist, I can see the need for a kit like the one Britec is pimpin' because you need to know you can plug something in and have it do all the work with just a few clicks at most. whether or not this kit qualifies for that task is a good question though. not everyone can or is willing to even figure out how to get into the BIOS to change boot order when necessary. maybe I should rewrite my old app for that purpose and distribute it on USB hmm...?
but as a computer tech you need to sell your services to live and eat. I say keep using DBAN or whatever utility is out there and charge ppl for the service, offering to physically destroy it AFTERWARDS for the extra paranoid and an extra few bucks.
I think this flash drive is purely for ppl who cannot handle using linux boot disks and commands and need something more automated/scripted. you as a tech can handle it.
you could even get the flash drive yourself, whatever; my opinion on it not being necessary isn't based on the technology of data destruction in this vs. DBAN or whatever, but rather on the idea that data recovery isn't as easy and not everyone getting your used hard drive is capable or willing to go to the lengths to get past whatever methods were used to destroy the data to begin with; the vast majority of ppl looking for data on used drives probably don't even use data recovery software like RStudio, much less some NSA type secret sauce utility. they're probably just looking for drives of ppl who don't even bother to wipe the disk or even delete their data at all, and surely that happens enough as it is. how many ppl who go through extensive recovery efforts keep it up when they find that grandma only ever went to facebook. I guess this is all another topic entirely though, and I should probably get back to work