Unless you're fishing for what would traditionally be considered big game species, you should be using tippet rings. It doesn't matter whether you're fishing machine-made extruded leaders, furled leaders or hand tie your own. Tippet rings have their place in all of these scenarios.
The reasons why are simple: tippet rings provide a significant amount of convenience and conserve tippet material. More importantly, however, is that tippet rings make your leaders last much, much longer.
A leader that would otherwise have to be repeatedly rebuilt, eventually getting tossed because you've tied one too many surgeon's or blood knots in your repeated efforts to reconstruct it, will last an entire season or more if you introduce tippet rings into the equation.