An audio interface module is great for starting out, but I let mine go in the end... why? I got a mixer that has tons of headroom and the capability to attenuate incoming signals - it's perfect!
Having said that, I still have an input module for external sources because they do need amplifying considerably to make sense in the modular world.
Gain staging is one of the mot essential skills in music production, if you pay attention to this, and make sure you never clip your signals - you will get better results faster. I spent years messing up before I fully understood this simple but absolutely critical process.