Besides the weight. Given the same amp guts, wondering if there is a volume level difference, sound difference or something else that would make someone prefer a 1x12 or 2x12 combo.
I'd say that is largely due to the bigger cab dimensions rather than more speakers. Some 1x12 combos like my Bogner Goldfinger have a bigger cabinet. Not boxy at all. More speakers will have more low end though.There are many threads about 1x12 vs 2x12 if you use the search engine. Many folks feel 2x12 are less boxy sounding. Just a little volume increase.