I don’t think there’s anything worth celebrating. While I don’t think Columbus was an especially cruel person for his time, he and his expedition were certainly savages by any modern standard. They enslaved and mistreated the native peoples they “discovered” and claimed their resources for foreign lands. That’s just fucked up.
I do think Columbus was hugely important in world history. If nothing else, look at how agriculture changed after Columbus. Italians didn’t have tomatoes; Irish didn’t have potatoes. Chocolate, vanilla and coffee were unknown to Europeans. Horses and cows were unknown to native Americans.
I’ve always been interested in how differently things would have turned out if the Chinese had “discovered” America before Columbus and set up a similar world trade. They almost did; in the early 1400’s Chinese mariners had a much larger and more complex fleet of trading ships than anything in Europe and had already established trading routes as far away as Africa. It was only a quirk of the Ming Emperor, who unilaterally decided to cut back trade, that the Chinese didn’t make it as far as the Americas.