It's not dust in the sense that it still has/had value at high fees. Last December, fees went up to 600-800 sat/byte (and shortly even higher). If/when fees go up that high again, each input would cost you 0.001BTC or more in fees, which is 10% or more.
Let's say you have 10 small inputs of 0.01BTC. If you consolidate them now, you can pay 1 sat/byte and get around 0.09998BTC as output. If fees go up to the peak again, you would get less than 0.09BTC. That's why it's so important to consolidate your funds while fees are low, it makes it cheaper to use your funds later on.