Prior to coming into this year's LCS, I knew nothing about League. Even when I drafted my fantasy team, I might have been playing for a week or two at most and had yet to see an LCS match. Essentially, I drafted entirely around projections.
Lo and behold I lost my league, but it was still a fun modifier to a traditional LCS viewing experience. If I had been playing for a large reward on the line, I might have felt differently about the whole thing, but overall it was just...enjoyable. I couldn't have asked for anything more.
For me, that anecdote relates because I would have no idea who to take for Worlds. But that's ok! There is this weird allure that would allow me to enjoy a team made up of people I know nothing about, understanding that I would be learning about them as the tournament progressed. Not everyone will agree with that, and they shouldn't, but if I'm only playing for bragging rights then I wouldn't have any qualms doing a Worlds league.
However, that lack of knowledge can present itself as a potential barrier in many cases, so it would be something to consider when deciding whether or not a fantasy league for Worlds is feasible.