Stored Goods and supply depot

It does not.  It gives a modest production bonus (10%) and morale bonus (15% + %/adjacency).  If you don't need the morale bonus, you'll be better off building a factory (as they upgrade to higher production bonus)

early game, the supply depot is probably better because of the limited amount of morale boosting buildings without tech. it does  impact supply goods because the more Manufacturing you have the more you produce extra goods. Like anything extra after building something goes into stored goods, or anything not enough takes from it. If you need the morale then it should out perform a factory, until later game. Typically early tho it helps to build it next to your colony capitals.

Good point, the supply depot does indirectly help with stored goods by giving a 10% bonus to production.