Yes, but has the final assembly been calibrated against a known controlled environment? Without that, the readings from the device become more of a crapshoot,

Yes, but has the final assembly been calibrated against a known controlled environment? Without that, the readings from the device become more of a crapshoot, which is fine if there is no desire for greater precision (i.e a just for fun project) Sensor manufacturers cannot calibrate for every possible packaging configuration. As someone who has DIYed a lot of stuff related to indoor climate, I tend to save my effort for the mitigation work, and use well tested measurement tools to validate those. This is for the same reason that one doesn't usually DIY a multimeter before doing electrical work.