In an eCTD (or NeeS/VNeeS) submission, PDF hyperlinking plays an important role.
Both bookmarks (outlines) or content links (link annotations) help accelerating the e-submission review process.
Never mind if you are submitting in EU, US or AU - all Agencies prefer links that are operational and valid.
What's more: best practices ask for valid file links, inherit zoom, no web links, visible bookmark pane and alike.
You certainly would not like to get an RTF (Refusal To File) because of a few broken hyperlinks in your electronic submission!