When the baseball team has to divide 11.7 scholarships amongst the entire team, it is a huge benefit to have a player on full scholarship via other means (football).
While I’m not sure how much Baseball would factor into Mario Williams‘ decision, David Pierce could absolutely use a fast, rangy, athletic player as a defensive replacement and pinch runner and would value a position like that over a 12th pitcher or fringe freshman. If there is any legitimacy to Williams’ interest in baseball, Texas baseball should absolutely try to help with that recruitment.
Furthermore, with the MLB shrinking the draft soon (evidenced by the COVID draft in 2020 and outspoken desires from MLB front office members), and more and more minor league baseball teams going away, college baseball athletes will be more marketable and players who would have gone into the draft will now be playing in college with fewer rounds in the draft. Absolutely bar minimum, Baseball would give Mario Williams a point of leverage similar to Kyler Murray.