Android is not exactly great to use as a desktop PC, so there’s been various attempts to improve this for Android boxes, tablets, and laptops for example with Remix OS, bringing a more desktop-like user experience. Rockchip showcased multi-window supports in some tablets a while ago, and now they have “Light Work OS”, an operating system based on Android 5.1 that feature a start menu and multiple windows support. PiPo even decided to use a background image with Windows logo in their PiPo X9 tablet powered by Rockchip RK3288.
The problem with Android used as a mini PC goes much further than the lack start menu or window mode, but copy/paste can be a pain, and things you take for granted on desktop, simply may not be available in Android apps: some graphics elements may not be clickable, some website features may not work properly (I’m thinking WordPress editing here..), mobile apps may lack features, and so on. So I’m not sure Rockchip will get many people who considered a Windows device to go for a Rockchip tablet with Light Work OS instead.
If you don’t care about desktop mode in your tablet, the good news is that it can be disabled.
Rockchip is not the only company working on Android for desktop, as Allwinner is also working on Double OS optimized for office applications.