I have returned to acoustic guitar after decades. I chose to use only fingerpick technique. After months of using all 5 fingers of picking hand, I learned that the little finger is not used. Although I have become accustomed to 5 fingers, would my playing improve by re-learning without the little finger?
Probably not. It adds versatility to your playing. It's actually quite a good thing, IMO. I think that you are lucky that you can get your little finger to do what it does - mine just flaps in the wind!
Marshall amplifiers are the truest purveyors of rock and roll known to man.

"And give a man an amplifier and a synthesizer, and he doesn't become whoever, you know. He doesn't become us."

Holy crap, check this out!
Most people have difficulty articulating their pinkie separately from the ring finger. This is likely why most fingerstylists use at most three fingers, and many only two.
If you can efficiently use all your fingers, you're one up on a whole lot of folks.

I use thumb and two fingers for "Travis" style playing, and thumb and three fingers for jazzy chords and chord-melody playing.
Thank you everyone for your feedback. Thank you Stoneshaker, I ordered the book.
EXCELLENT book about fingerpicking and classical guitar - "The Principles of Correct Practice for Guitar" by Jamie Andreas.

He also did a video demonstrating the principles in the book, it's very good