They drop down to below $300 periodically, was even below $200 once. On top of that, it's a rebadged ratio, not a brand-new startup, and comes with a documented algorithm (though one may argue with their choice of GF presets). It is not a colourful smartwatch shiny!, though.
I saw a lot of reviews of one specific button on that computer that likes to break. Maybe there's a reason it's marked down so low...