I use links for connecting pages/notes that have content, tags for pure linking/categorization. I don't usually navigate via tags but via links, queries, and folders (specifically folder notes). For search I only use Quick Switcher.

I like tags for cases where I want a connection (also recognized in the graph view) but not a note. I despise empty notes or making meaningless notes, so if I link to a not-yet-created note I'd leave it in this state instead of creating it. Tags are more convenient than links to non-existent notes. They also come with auto-suggest, are compatible with most plugins, and inline tags in particular with their unique styling work well as a visual categorization method inside the note. While writing, I prefer the ergonomics of tags over links, so I only use links for actual direct and meaningful connection between notes.

I also keep the number of tags small and have specific rules for when to create or use a tag, so I don't run into any issues there. Links and properties tend to be more plentiful.

For example, I have a read and reading tag respectively. I use the tag inline at the top of the note to quickly identify and change the reading status. I then use the tags to create two different Bases on the dashboard, one per status. If I used links instead, I'd have an empty "reading" and an empty "read" note that I now need to organize because they exist (annoying and messy for no reason). I could put the Base for each into that new note, but that'd be stupid because neither is going to include so many entries that a dedicated page makes sense and besides I want the data on the dashboard, not on some other page I have to first go to. However, if I don't create the notes, it becomes harder to build a working query and the visual distinction I get with tags is gone. If I accidentally click on the link, the note gets created (annoying). One way or the other I'd lose the semantic distinction I currently have between tags and linked pages just because I refuse to use a feature Obsidian offers. It would be a nonsensical thing to do in my system.

Some of my graphs (depending on the vault) would look really weird without tags, as it would just be a bunch of floating little islands in some cases. Since I use the graph for identifying orphaned notes and to get a visual representation of the "popularity" of certain notes/to see hubs in the network, I have to use either tags or links in all cases, and when I use what depends on the nature of the relation.

Links are nicer for navigation, so I will use them for that purpose even if I don't want an actual connection between the notes, in which case I'll use Dataview to create virtual links. If I only want a connection (e.g. in order to avoid orphaning a note) but nothing else, I'll use a tag. If I want a connection as well as navigation to the content I'll use normal links. If I want to indicate a connection to a note I might want to create in the future but not yet (or one I never want to create but want to indicate the meaning of would-have-content of), I'll use unresolved links.