To be fair, I like the idea of using thermal printer, so this could be only thing I would consider using, but I don't like it's using bluetooth for communicating with device.
Keep in mind that thermal prints
can degrade extremely quickly. For example (duh) by being exposed to heat, such as laminating the print or just storing it in a hot place.
You can try e.g. leaving a thermal printed receipt in your wallet for a few weeks and the writing may become illegible. It depends a lot on the paper and other factors, but generally not my preferred way for seed storage.