Heated coasters generally continue to heat such that the temperature is constantly rising, cooking the coffee so that it’s burnt in short order. After a certain point the coffee can either become too hot, or undrinkable, especially if you’re unable to drink it for a while, due to work, or other distractions.
Then there’s the issue of transportability. The great advantage of this cup to me, is that I can walk around the office with it, take meetings, drop by a colleagues office, chat by the water cooler, and when I get back to my desk it’s still the perfect drinking temperature.
I can’t imagine going to a meeting carrying a mug and a heated coaster, looking for a place to plug it in, which probably means stretching a wire across the pathway to set it on the conference table. I’d look like an idiot.
I can’t relate to that first scenario- mine does not burn or overheat my coffee. I set it to the desired temp and it keeps it reasonably heated. It’s not perfect, but for $20 it definitely gets the job done in a satisfactory manner.
Regarding your second scenario- That’s such a specific use-case that I can’t see that being a selling point. If that works for you- great! I’m glad it solves that problem. But paying $140 so I can keep a cup of coffee heated during a meeting while not looking like an idiot is just not something I worry about.
The people in my office drink their coffee so quickly that it doesn’t get the chance to become cool anyway.
Again I’m not saying that it’s “useless”- everyone’s needs will be different. But at that price point, it can’t become more than a novelty item for those that like these kinds of techy gifts- or for someone that *really* has a cold coffee issue.