Tea from a bag in a mug is fine. Tea made properly is a different drink, and most people never get there because it involves too many bits of kit spread across the counter.
This is glass, so you watch the whole thing happen. The leaves open up, the water takes on colour, and you can tell when it is ready by looking at it instead of guessing from a timer.
Glass also stays out of the way of the flavour. No metallic edge, nothing held over from whatever you brewed yesterday, no lingering smell from a herbal blend the next time you make something delicate.
The body is built to take heat, so hot water straight in is not a problem, and you go from brewing to pouring without moving anything between containers.
Green tea, oolong, herbal blends, fruit infusions, loose leaf or bagged. It handles all of it, and plain hot water when that is all you want.
Wide enough at the top that filling and cleaning are not a fight, which is more than can be said for most brewing pots.
It also looks like something worth putting on the table, so tea turns into something you serve rather than something you carry back to the sofa one mug at a time.
