The argument isn't so much that you can reach across and do everything independently, it's that seeing the underlying code makes collaboration easier. Sometimes

The argument isn't so much that you can reach across and do everything independently, it's that seeing the underlying code makes collaboration easier. Sometimes it means you copy/paste links to the code into Slack to ask about them. Sometimes it means you open an MR and ask for review because you're not sure. But both of those are highly preferable to opening a ticket for a different team and waiting around for maybe someday they'll get around to tackling something that a) the Business didn't ask of them and b) they didn't open for themselves