You are right, while there are already some libraries which provide GA, there are almost non which use it. I know that it is used in some photogrammetry pose es

You are right, while there are already some libraries which provide GA, there are almost non which use it. I know that it is used in some photogrammetry pose estimation / frame registration code and I am currently porting my vector / path rendering library to GA. It is still really niche, but gaining traction in the last 3 years or so (considering it was invented in 1878).