ADU or not: Basement Only Needs Kitchen

[Dan Perron]

Advice/thoughts needed! I'm stuck in my analysis of a 5BR/3BA (upstairs 2BR/2BA, downstairs 3BR/1BA) house in San Diego. The basement (rare in San Diego - it is positions on a sloped canyon rim) is completely finished with a walk out entrance and compliant (I think) windows. To make the basement a separate independent living space I would just need to put up a separator at the stairs and add a kitchen (and a few other things, I'm sure). I am trying to figure out why I would go the ADU permitting route.. wouldn't that just add more time/money?

The main advantages of getting it permitted I could see are 1) potentially added value to the equity of the home (but questionable how much) and 2) separate address for the basement ADU, making mail delivery etc more straightforward?

What other advantages of getting the basement officially permitted as an ADU am I missing? I wouldn't take any shortcuts in the kitchen build and would make sure all is up to code/safe.

Any advice on things to look for in terms of adding a kitchen to the basement?

Basement is basically exactly 50% of the total sq footage of the home, so I'm good on that regulation. 

I should also note this home also has a sizable attached 2 car garage that could later be converted to a jADU.