The second reason is Universal has obvious benefits that are easily communicated. Convincing people of the benefits of a costly road/train track paid for by the taxpayer is difficult. Selling 10,000 extra jobs and £10bn investment from private companies is easy.
The third one is the name. Even those who don't go to Orlando probably see the place as quite touristy, flashy, fancy, full of fun, and a bit magical and mysterious. Whether that's true or not doesn't matter. The same connotations hold with the idea of creating Orlando in the UK (even if the reality if far from it).