If you think the walls will look better painted, go ahead and do it, but be aware that it may peel readily as the concrete does allow some moisture migration.

As for decreasing humidity, putting anything on the walls will not do much, if anything. Warmth always migrates to cold. In the summer, warm moisture laden air enters the cooler cellar and condenses. The old practice of opening windows and bulkheads in the summer actually leads to more, not less moisture in the cellar.

We're also moving from a small old house to a larger old house, the only difference being that the new basement has definitely had groundwater intrusion (we're on the coast at sea level). The basement walls and floor have also never been painted since 1910.

We'd like to spruce up the basement laundry area in the new house, so we asked the same question of our house inspector last week. His reply was that it's actually not a good idea to use Drylock on a block foundation, since that traps groundwater moisture up against and in the block, which in turn will freeze inside the block in the winter, causing foundation cracks. It's anecdotal, but it did make sense to us, particularly as this unpainted block foundation is very structurally sound and still going strong after 102 years. So we're kinda going with "ain't broke don't fix it".

In terms of the concrete floor itself, any coating eventually peels and comes off, looking worse than before. But there are epoxy-based floor paints that I think hold up reasonably well, if you take regular maintenance into account.

Enjoy the new old house!