Internal links and backlinks both matter. They solve different jobs.
Backlinks are references from other sites. Internal links connect pages within your own site. Teams sometimes overspend on external links while their best pages are hard to find internally.
What internal links do well
Help users navigate, help search engines discover pages, distribute attention across important URLs, and clarify topical relationships. A brilliant commercial page with no internal support is unnecessarily handicapped.
What backlinks do well
Bring independent references, support discovery from outside your site, contribute to competitive strength on harder queries, and drive referral traffic when publishers have audiences.
Which matters more?
It depends on the bottleneck. If your site architecture hides key pages, fix internal links first. If the page is excellent and still loses to stronger externally supported competitors, backlinks become more important.
Many sites need both, in that order: make the page worthy and reachable, then earn external support.
Practical internal linking rules
Link from strong related pages to money pages with descriptive anchors. Avoid orphan pages. Update old posts to point to newer definitive guides. Keep navigation honest.
Final answer
Internal links are the control system inside your site. Backlinks are outside references. Fix internal discovery and page quality before buying external attention you are not ready to use.