History
Having realised with the LC series that users were more than willing to sacrifice cutting edge technology for a saving in the wallet department, Apple set about making the low cost world of the Mac even more easily accessible and aimed to turn what was an already simple machine into an absolutely idiot proof machine.
Bundling processor, screen and speakers into a single box, the LC 520 did away with having to plug (some) cables in and created a machine that worked just about straight out of the box and therefore appealed to those potential users who had a complete techno-phobe mindset.
Under the hood though Apple saw a way to re-use technology and, despite the new all-in-one case, the LC 520 was actually a regular LC III - the only change being to add a built-in microphone.
At a price that made owning a Mac a realistic opportunity Apple managed to capture that all important quality that, for some machines, had been painful lacking ($10,000 for a desktop machine such as the Mac IIfx was pure fantasy when applied to the non-business user).
The LC 520 was a decent machine which was especially popular in the school market, and it's all-in-one design meant that the swathe of cables that were usually associated with desktop machines was neatly swept under the carpet (not literally).