I have read comments in multiple places, both on photo.SE and elsewhere, that superzoom lenses are not good and that most people will be better served by buying two zoom lenses, each spanning a smaller zoom range.
Specifically, I own the Sony NEX-5R, with the 35mm Sony F1.8 and the 19mm Sigma F2.8. I'm trying to decide whether to buy a superzoom lens, specifically, the Sony 18-200, as opposed to a non-superzoom lens like the Sony 16-50 or the Sony 18-105.
From DXOMark, the 18-200 has a perceptual megapixel score of 5 megapixels, while the 16-50 has a score of 7 megapixels. This seems like a small difference. Why do superzooms have a bad reputation? For comparison, the 35mm prime has a score of 11 megapixels.
Even 5 megapixels is not a significantly higher resolution than my 15-inch Retina Macbook Pro (5.05 megapixels) or my 30 inch monitor (3.9 megapixels). So it looks like I'm not going to notice the supposedly worse performance of the superzoom. I don't pixel-peep or print out my photos.
Note that I'm not looking for the Nth degree of optical performance here. I wouldn't pay hundreds of dollars for a small difference in performance (F1.4 vs F1.8, for example), or inconvenience myself by carrying and changing between two zoom lenses instead of one superzoom lens, if the differences were not visible to most people.
Is this analysis and conclusion correct?