What are the advantage to using something like sky connect vs a dedicated/standalone matter hub?
I understand that using the aeotec hub has the disadvantage of exposing matter devices through a smart things interface which means you lose functionality and do not get cloudless integration. But there are other edge routers or there.
the hub can be placed flexible were you might need it 
Well, very unfortunate. 
Matter is (was?) here to don’t repeat the mistakes the Zigbee Alliance made - they even changed the name to Connectivity Standards Alliance because… well… don’t know. 
Actually it is/was to be expected. Not deep into this (avoiding z/matter-stuff) but I think it was added to the matter standard shortly before finalizing that it is (ones again like with sh!tbee 
) allowed that manufactures only expose a minimal/base set of functions and keep others walled in there ecosystem. 