I don't know how dense I am but I must be thick as I have no idea what any of these things are!
Open heart movement and Tourbillon movements look similar, a cut-out of a circle, showing the balance wheel (the wheel that oscillates as the heart of the watch ticking, powered by the spring).
Open-heart watches solve this problem. These pieces
offer the wearer a glimpse of the working movement through an opening on the dial. Usually, it features the balance wheel working, which gives the impression of a beating heart. This results in a very visually pleasing sight.
Whereas a Tourbillon looks similar, but rotates the entire balance wheel, spring and gubbins as it oscillates, negating the effect of gravity variation and movement over time, making the watch movement more accurate as a timekeeper.
"A tourbillon is a mechanism that
constantly rotates the balance wheel, balance spring and escapement while the movement is running. This is done to counter the affect of Earth's gravity on the isochronal properties of the balance wheel and spring. The tourbillon was invented by Breguet in 1795 and patented in 1801
."
These are more complicated to make and engineer.
When the open circle in the dial showing the balance wheel is displayed, to the uninitiated, like the Chinese sellers and non-expert watch reviewers and resellers, the oscillating balance wheel in a cheap open heart watch can be misinterpreted and mistaken as a Tourbillon moving & rotating balance wheel & movement.
On TV shopping sites, open heart mechanical or usually automatic movement watches can be £30 to £200 compared to Tourbillon movement watches starting at £1k+.
Higher end Tourbillon movement watches can be anything from £10k to multi £100,000s plus pounds from high end makers like Jaeger Le Coultre, Patek Philippe, Vacheron Constantin, A. Lange & Söhne, etc.
Tourbillons are a bit of a status symbol for some, a means of showing their wealth by owning an expensive Tourbillon watch.
Turns out a Brit actually had the idea and invented it according to wiki:
In horology, a tourbillon is an addition to the mechanics of a watch escapement to increase accuracy. Conceived by the British watchmaker and inventor John Arnold, it was developed by his friend the Swiss-French watchmaker Abraham-Louis Breguet and patented by Breguet on 26 June 1801.
Wikipedia