The best thing about Grabby imo, I'm able to use a custom camera app from the lock screen in the same way as the stock IOS camera app, with no passcode.
Granted it's not as secure/polished as the stock app's implementation as it doesn't take ProCamera (for example) into a sandbox mode where I have no access to existing phots, but it lets me straight into the camera and if I want to unlock normally, I'm prompted for my passcode.
I'm reading that Axis doesn't do this, and plus I've already purchased Grabby for that one reason alone, so not going to buy something that offers nearly the same functionality for less.