Not sure but I assume that the Octavo Systems OSD3358 uses the same parts as the BBB core processor/memory/misc. Which means at least you can load the same firmware as a BBB. Which leaves you with the same trust issues as a regular BBB. If that's not true then all bets are off.

Me I'd be more worried about the WiFi module, thought stopping to think, if the WiFi module driver isn't open source that's a worry too.