Sealant in inner tubes: what's the difference?
Putting sealant in your tube does nothing to prevent pinch flats. (The long gashes caused by pinch flats would normally be too big for the sealant to handle, at least reliably.)
Putting sealant in a tube adds to the weight of the tube, rather than replacing it as in tubeless.
Likewise, with sealant in a tube, you have all the rolling resistance you already had with the tube, plus more energy cost to turn the wheel due to the sealant. (Bicycle Rolling Resistance tested this.)