My experience on the 2015 MBPs is that going from 512 to 1 TB adds $25 to $50 to the price. That's probably a fraction of the original cost differential. If you're going to sell this five years down the road, SSD storage will come down in price and newer models will have twice the storage at the same price point.
If you don't need the space, don't get it if you're looking for higher resale value.
One option I'm looking at: it looks like I will have to get some kind of a hub. It may be that there are hubs that have one or more SD slots and that I could just leave the SD cards in the Hub all the time for extra storage.