The biggest difference is the chemical composition. GS30 belongs to Chloroprene rubber, while silicon made from siloxane.
GS30 is cured by volatilization of solvent (fast curing), and GS30 contains solvent;
Silicone does not contain solvent, and it is cured by moisture in the air (curing slowly).
In terms of function, GS30 contains oily (solvent) rubber components, so compared with silicon, GS30 has excellent adhesion, toughness, weather resistance and others.
GS30 is suitable for vehicle repair or outdoor adhesion; the DIY or general decoration will use silicon.