Battery storage could earn you more if you discharge at the right moment, but energy prices aren’t negative often enough to warrant the expenses on a battery pack. You could also trade on intra-day pricing differences (buy low, sell high) but I doubt this will be an interesting business case for the average consumer.
Of course large scale battery parks work the same way, but they will have contracts with the grid provider to balance capacity, a more lucrative market.
Large scale electrolysis has the same problem as home batteries: big investment, so you won’t recoup the investment unless you can run the electrolyser often enough. Another issue is that electrolysers can’t scale up or down very quickly, so you can’t respond to capacity issues and get lucrative deals in that market.