Could you clarify? Do you mean that those methods provided more species-level classifications than classify-sklearn?
Or do you mean that classify-sklearn resulted in more unclassified sequences?
I suspect you are describing the first. This is not to say that those species-level classifications are wrong, but you just don't know that they are right (unless if you are testing on a mock community). With short sequence reads it can be quite difficult to obtain reliable species-level classifications; classify-sklearn is designed to handle these cautiously and only give a genus-level classification if it cannot confidently assign a species.
at the end of the day, though — stick with whatever method you like the most. I'm not arguing for one over the other, just highlighting a philosophical point. 