The Cheapest Lens “Speed booster” – Does it suck?

The Cheapest Focal reducer / Speedbooster lens adapter I could find… it it any good?
Gorilla Film Gear Focal Reducer Canon EF EF-S Lens to Micro 4/3 Mount Camera M43 Speed Booster Review

Focal Reducer Canon EF EF-S Lens to Micro 4/3 Mount Camera
https://gorillafilmgear.com.au/focal-reducer-canon-ef-ef-s-lens-to-micro-43-mount-camera.html

Focal Reducer Nikon G F Lens to Micro 4/3 Mount Camera
https://gorillafilmgear.com.au/focal-reducer-nikon-g-f-lens-to-micro-43-mount-camera.html

On Amazon Australia (doesn’t seem to be listed on the main US site?);
https://www.amazon.com.au/gp/product/B07B8J81J6/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1