[Moz]

I use my ultra-light set up for trout on river smallmouth bass too. You generally need smaller lures for smallies and the 4 LBS test helps not to spook them and it's great fun to fight them on it. You can also use this kind of set-up for panfish so it's pretty versatile on a number of species including dink largemouth bass.

I'd never use that light a set-up for bigger Largemouth bass though as bigger lures work better (at weights which will exceed an UL rod's rating) and you have to fish off structure and cover and 4 LBS test won't hold up to the abuse. I use 8 LBS test in the open, clear water I fish in because of the smaller diamater and I primarily fish with weightless plastic lures that I want to cast further. My main LMB rods though have heavier-rated fluoro and braided lines on a meatier rod.

A medium-light rod could probably do a little of both. Maybe invest in a good reel that comes with a spare spool so you can swap lines for whatever you're fishing for that day.