Credit monitoring/insight feature questions

It seems many banks and credit cards now offer a means to show one’s credit score “without affecting it” and offers tips on how to better the score. I have a few questions :

• what’s the catch ? what are they getting in exchange for proving it for free while credit agencies charge ?

• while my score is good , there’s still room to go to 850. The feedback I’m getting (Amex uses FICO 8 based on experian data ) states :

  a) “lack of installment loan” (which is accurate , I paid off my car early) . Feels odd that paying a loan off is a negative.

  b) “length of time account has been open” which is odd as I haven’t opened CC accounts in a long time. Do bank accounts fall under this category ?

Other than actually getting an installment loan (which seems a bit excessive :) ) I don’t see much wiggle room to make things better here. Am I missing anything ?