My experience this past March had me earning zero point and stay credits at a Hilton property when booked through the Canadian AMEX online portal. I did receive my elite benefits, including full complimentary breakfast, but that may have been due to my adding a day before the AMEX booking that I reserved through Hilton. For that particular day, I did receive my points and stay credit. I also received a one category upgrade from the original suite I booked to a better positioned corner unit with a balcony. Years ago, I booked a Marriott property through PTS by phone and received all points, stay credits and elite benefits. More recently, but before COVID-19, I had twice booked an IHG resort through AMEX online and received stay, but not points credit. I would say it's definitely YMMV, with most bookings not receiving any loyalty credit.