Well, where you're fishing is a factor. Even where I live, I've had my backside handed to me with 4 lbs test on a few occasions, so I have chosen to not go quite that low. I'll fish with 6 lbs mono where I live all day long with BFS gear. Still, you'll have to pick your places out carefully to fish with BFS gear in your neck of the woods.
My biggest Texas bass (8.5 lbs) was caught on a 1/4 oz slab with 8 lbs test on a spinning rod on the Community Hump (no side-eye, I didn't pick the name of the spot) at Lake Fork. The same place where I have been destroyed with 15 to 20 lbs line on other occasions. Even on a lake like Fork though, there are places where there isn't much cover and you can fish with lighter gear.
KastKing has a few different models of the Kestrel IIRC. The Kestrel, the Kestrel Elite, and the Kestrel BFS. I don't think the original Kestrel is still a current model. The Kestrels are all (IMHO) BFS-ish, but the Kestrel Elite is more BFS-ish (and newer) than the original Kestrel, and I will go out on a limb and saay that the even newer Kestrel BFS is a little more BFS-ish than the Kestrel Elite (but the Kestrel Elite does have a better build quality than the Kestrel BFS).
If you have the original Kestrel, if you pair it with a light or medium light rod and maybe 6 or 8 lbs line, maybe it would be a more satisfying user experience and not quite as impractical in a wider variety of places where you live. You can have an absolute blast catching two to four pounders on a setup like that, and if the water is a little more open, you can definitely have a chance with fish up into the double digits, even on 6 lbs line. You can fish Texas rigged plastics and get a hook set into a bass with 6 lbs line. You can also fish small jigs, weightless plastics, underspins, slabs, poppers, small topwater plugs, crankbaits and jerkbaits. You do have to be careful to not fish thick wire hooks, and keep them sharp.
It'd make a dandy crappie rig too.