No airline in the US does flight physicals, however the 1st class medical is required by the FAA, to operate 121. You being a hot shot private pilot should know that some of this… And to clarify any place you want to rent an aircraft is going to give a checkout, its generally required by insurance, on top of making sure you can actually fly.
Having been an XJT pilot for 14 years, furloughed for 2yrs, now (thanks covid and Kirby), not having to jump through hoops like an interview is nice. Not all the pilot’s they pickup will have the option for the left seat unless they have to time to jump in the left seat… hell I still considering coming out of a cushy work from home, back to flying because of their offer, and being on the training side. Its a lot of money, more than 1st year AA, United, even Delta, even for the short term of the temporary contract in place.