It's also easier to handle the spawn that comes up with the SOSes themselves (you can solo the serpents easily enough, though). Also it gives you some more firepower to do nets with between SOSes, which can net you some mibs from Kraken. You'll get about 1 MiB per hour, as Xonryz mentioned, at least at GM. Investing into some fishing scrolls will pretty much double that per scroll used. I've pulled up like 5-6 in a couple of minutes, pretty much back to back, and that didn't include the nets and plain maps. Granted that was at 120, but it is an investment-based skill. Running a 120 and a 110, for example, is exceptionally easy, very profitable and extremely safe to do - given you're licensed with the Trinsic Trading Company, of course.