It is possible to pretty much emulate the tone with a pick, if you know where you're at. It seems not everyone can do it, or even want to, but I can and know other players who do.
Play with fingers because it feels better, or its more dextrous for you, or whatever, but the idea of a unique finger tone that can't be replicated is simply incorrect. Indeed, the available tonal palette from a pick is far, far wider in range.
My band member chums can tell from a recording whether I'd gone at it with a pick (which is more usual) or fingers. Sometimes I myself have to check my own written notes to establish that one, because when I want to no bugger can tell the difference.
Im on the fence. Im mainly a pick player because of injury, but do play fingers from some parts and would play a bit more if my missing dexterity would let me. Do either because feels right for you, but this idea of a unique finger tone is pretty much a nonsense.