What is the advantage of using threaded fasteners to secure structural components as opposed to welding or adhesives?

It is easier to remove something screwed in than something glued or welded in.

Further threaded fasteners go deeper than adhesives, giving more of the object to hold onto than just the surface areas. This is good for anything attaching to wood which is a softer material.

Stainless steel doesn't weld too well, particularly to non-stainless steel, so fasteners may prove an easier alternative. As I heard that stainless steel is cheaper it can save money as well.

Different types of metal or even different thicknesses of a metal can be hard to weld or just may not be weldable at all and so fasteners are needed.

Sometimes a weld can can be brittle and snap or an adhesive wear away from small movements. Fasteners can be more reliable if you're not a pro.

Fasteners can be cheaper as well in many circumstances. A drill is usually cheaper than a MIG Welder. lol.