@XM Could be used for good or evil. I've had to test mobile payment apps that required some load testing. Only way to do it sometimes is with real devices issuing real requests. Provisioning a new card into a mobile wallet is a good example that's hard to emulate.
And...they could very well be bad-bots. Just chunking out Amazon reviews or propaganda.
@XM I would also add that mobile apps sometimes need specifically tested against as many makes/models of devices as is practical. I don't think that's the case here as many of those devices look exactly the same.