I’ve got 4 and 5in droppers, with and without remote. I’d say 5in with remote is def worth paying for.
I use mine constantly on every ride, not just on the steeps but anything rough, techy or jumpy – it just gives you more room to move around and get your weight in the right place. I find it especially handy when riding flats because you’re moving your feet about on the pedals more and, without a dropper, saddle height is always a compromise IMHO.
I almost never used to drop my saddle in the bad old days.