marketing, brand image, any of the other dozen things that mask bad engineering quality and sell the customer on some superficial thing.
Not just in cars but a ton of consumer products customers can easily neglect engineering quality in favour of some gimmick.
Hell even developers constantly choose convenient or shiny technologies over ones that are robust or error free.
Tesla could win, with shoddy engineering, if they can convince the public and government (using the classic reality distortion field :) ) their self driving tech is ready for prime time (when, for the sake of argument, presume it's not ready).
They could then use the investment dollars generated to take it to the next level and perhaps make it solid over time -- but it could take a long time.
In the mean time, the public was effectively deceived as to the true safety level of the product. I would prefer if the opposite happened instead.