It makes a difference to stress and strain on wing loading vs fuselage loading. Single-ish points of contact of the wings with the fuselage are able to sustain heavy wing weight on the ground, heavy wings supported in the air and light wings as they empty of fuel.

But if all the weight is in the fuselage, there is no opportunity for heavy wings on the ground or in the air without significant increases in wing-fuselage engineering which comes with attendant weight.

Fuel or batteries in the wings or nacelles counts differently than weight in the fuselage.

Mechanics.