Purposely leaving small amounts of crypto on your device is like leaving a few dollars in the console of your car. It lets you know if your property has had it's security breached.
How? Like someone would have to have access to the device and also know how you hid the crypto and then presumably despite having the former decides to only take the latter. Unless I'm misunderstanding. Like crypto is cool, but you know what's a cooler, a phone that also has crypto in it.
I think they mean you can see if you've got malware or something. Basically if you download something you shouldn't, I think their theory is it'll go for the low hanging fruit of a crypto wallet.
Yeah, this was my thought process. Security comes in layers and a huge amount of malicious software will scan for and send away unencrypted crypto sitting on a device. Setting up a small honeypot and monitoring for transactions gives me slight peace of mind. I just wanted to share my shower thought.