Tea is popular, but mostly blended tea from teabags, served with milk. If you ask for "tea" with no qualifiers this is what you will get. High quality tea is hard to find in offline shops. I do like good tea, but I mostly drink teabag tea with milk because of the cost and convenience, and I don't see how any tea robot can win on those features.
One important factor that Americans might miss is the ubiquity of electric kettles. We run 230V nominal (in practice still 240V) mains, and 3KW kettles are standard, so boiling water is much faster than it would be in the US.
Yes, I think many people prefer loose leaf tea to traditional tea bags.
It was a challenge to heat the water quickly on 120V, but I think we have a good system. It not only provides instant hot water, but also allows you to adjust water temperature.
I think you would have a much harder job promoting your product in the UK. Tea in my experience is something you might have instead of a glass of water - always produced with a teabag, which is very cheap, and with consistent taste (it's not something you drink for the experience, it's something that's part of your daily routine). It's not something you'd go out to drink (quite unlike coffee), and many people will have never had loose leaf tea. Every house will have a kettle, although it might not be used for tea.
There's also no real value in (say) a company offering highly premium tea to their workers - specifically although there is a bit of a hierarchy with tea (Basics, PG Tips, Yorkshire, Twinings (which specifically tastes different in America, so far as I can work out)), if you grab a big box of Yorkshire Tea (<5p per tea bag, less if you buy in bulk) no one has any reason to complain, and the picky person will bring their own tea to work.
This is quite unlike coffee, where there's a big trend towards hipstery coffee shops.
I'll definitely check out your machine the next time I'm in Palo Alto!
One important factor that Americans might miss is the ubiquity of electric kettles. We run 230V nominal (in practice still 240V) mains, and 3KW kettles are standard, so boiling water is much faster than it would be in the US.