The downsides are plentiful, however. For one, using the Web as your platform and self-distributing means that you do all the work: you do all your own promotion, all your own website building, all your own manufacturing. You'll be doing a lot of work that has nothing to do with drawing or producing comics. Also, your income will not necessarily be steady or reliable and will likely come from multiple sources. Ironically, the bulk of your income will probably not be from the comics themselves at all, but rather from sales of merchandise that is supported by the comics. The model of success, currently, seems to be giving away the product — the comic — for free, and making money selling things like mugs, t-shirts and advertising.
The Internet has been extremely disruptive to a number of creative fields. The music industry is seeing a similar shakeup, and there a many musical acts coming up today who use this very same model to make money and promote themselves. They effectively give their music away for free in order to lure fans into buying t-shirts and pins. People really like t-shirts!
(It's deeply ironic that, nearly twenty-five years ago, Bill Watterson himself railed against the efforts of the syndicates to license the work of cartoonists for the creation of plush toys and other such merchandise, and yet this is now how many contemporary cartoonists survive.)
In any case, self-publishing is probably the way to go for me, and probably the way to go for a lot of cartoonists right now and for the foreseeable future. I imagine some day that the syndicates will figure out a way to survive in this new ecosystem, but it remains to be seen whether or not this will be of any advantage to the cartoonist.