... it will be more of a toy than tool
I have to agree with you to a point. The fact that it's over $300 I'd have to say it'd be an expensive toy. However, to use this as a tool to gather empirical data for a engineered item that is being tested for something like an aircraft (DO-160 and such) I don't think it could be used. Our FLIR camera is sent of once a year to get it's official CAL. The items used to calibrate the camera, mainly blackbodies, are also calibrated (really just measured) and tracked. I doubt this will ever be used in any kind of official capacity. But certain a cheep way to get that warm and fuzzy that your product is preforming thermally the way it was designed before heading off an official lab for score.
Still, I'm going to try and have our ENG department snag one of these up to put on our lab iPhone we use for testing communications with our products <router, SATCOM computer, etc.>