Why is L hiding his face?

Question

At the start of the series L hides behind a computer screen which draws criticism by members of the Japanese Police who were assigned to track down Kira.

while in the context of the Kira Investigation in how the Death Note works and L's correct reasoning that Kira needed a face and name, hiding his face initially is a good defense against the Death Note.

When she was saying about how she met L, Naomi Misora said she worked under L by taking orders from a computer screen. this sounds just like how L was working at the start of the Kira Investigation and since the BB Murder Cases (which L comments is where he remember Naomi from when told she was missing) had nothing to do with the Death Note this means he was hiding his face not as a defense against Kira.

So why was L hiding his face before taking on the Kira Investigation?

Answer 1

Presumably to both keep himself safe and give himself business.

L has presumably put away a lot of people. Probably incredibly smart people, given that it required someone at L's level to catch them. It's easy to see at least one of these people holding a grudge or having friends who would want revenge. Keeping his name and face secret offers him protection. Good luck trying to kill a garbled voice coming from a computer.

Also, remember other measures L used to keep safe. Anyone wanting to contact L had to first go through Watari (who also used an alias). This further cements the idea that L just wanted to stay safe.

Furthermore, by keeping his identity secret, it allowed him to move freely. He could live a normal life, possibly fit in at a college (say to try and trap Kira, for instance). If he was publicly known, this would have been impossible.

On top of all of this, he used other aliases for himself (also for safety and possibly for business reasons). Remember Eraldo Coil, the number 2 detective in the world that the Yotsuba group hired to find out who L was? That was L too. It gave him a way to deflect someone looking into who L really was. It also was a good way to generate business. If you couldn't afford or get the interest of the almighty L, maybe the number 2 guy would be good enough?

_{I don't currently have access to the shows or wiki to be able to confirm some of this, but this is what I remember from having re-watched it somewhat recently.}