No, this device doesn't work when connected directly to an MST hub, a DisplayPort display, or a Mini DisplayPort display.
If you need to connect multiple displays to your Thunderbolt™ 3 system, you should use a Thunderbolt 3 adapter. StarTech.com offers a Thunderbolt 3 to Dual HDMI adapter (TB32HD2) and a Thunderbolt 3 to Dual DisplayPort adapter (TB32DP2).
Note: To use the TB32HD2 and TB32DP2 adapters, your Thunderbolt 3 system must support dual displays. For more information, refer to the following FAQ: https://www.startech.com/faq/thunderbolt-3-dual-monitor-adapter-single-display-only.