I know they market mars hard, but the more relevant thing this is enabling is the starships that will be used for the NASA Artemis missions and upcoming moon base efforts. Those missions are going to need a few heavy flights each for the lander and a re-fueling ship, in addition to the SLS + Orion capsule for the actual astronauts.
Still wish the money was being invested in NASA to do themselves, and that it was being done without all the waste and environment destruction SpaceX so enjoys, but this is still a big deal to ensure Artemis happens.
I'm not even going to get into a discussion of NASA competence. There are more than enough records available through widely accepted reporting and media to disprove any of the nonsense Elon cultists spew. Whether you subscribe to the Elon cult mindset or not is your prerogative and not an accusation I'm making..
Additionally, a significant amount of the funding for starship is coming from NASA, specifically from the Artemis program, to the tune of nearly $4 billion.
Elon can scream "mars" all he wants but he has virtually zero progress to report other than some wild plans to just throw people in tubes in the general direction. Last I checked, unless I've missed something, SpaceX has not put any amount of work into what is required to keep people alive on mars, much less alive on the trip to mars, and seeing as Elon's track record on delivering promises by self-imposed deadlines is basically 0%... We'll see if it ever even happens. Especially since he changes the goal post upon "delivery" (see: full self-driving basically never happening on top of killing more people per car than any other self-driving technology, cybertruck having a fraction of the features and capabilities that were promised on top of being extremely unsafe, semi being a massive failure, that ridiculous re-invention of the subway but for cars that makes 0 financial sense, and probably many more items I'm not thinking of at this moment)