I mostly deal with Hilton brand hotels for both work and our newish “hybrid digital nomad” lifestyle where we hop across cities in the US for 7 months a year.
We stayed in Hilton brand hotels for around 160 days over the last year.
You don’t get loyalty points and days don’t count toward status when booking through a third party. With Hilton, those loyalties points can account for 20%-35% toward future stays. Meaning if I spend $100, I will get points worth $20-$35 toward future stays. Based on rooms I’ve already booked this year with just points, we are staying free for 25 days in 5 cities this year. Of course point accumulation is a lot slower for most people. But there are a lot of people who stay in hotels using other folks money when traveling for business.
Most hotels chains also have a “lowest price guarantee” where they will match a price found on a third party site.
This isn’t even mentioning all of the hassle you can avoid dealing with hotels directly if things go wrong or if you just don’t like the service.
Last year, I booked a 7 day half work half personal stay in San Francisco at the Hilton Financial district. It was a run down dump. I went to the front desk, told them I would be cancelling the rest of my stay and booked another hotel - the Hilton Parc 55 - for the rest of the week.
The first hotel charged me for one night. That would have been much more of a hassle going through a third party site. First you would have to hope that Hilton gave the money back to booking.com and then go through the hassle of getting your money back from them.
On that same note, I booked a regular room at Parc 55, messaged the hotel on the app before I got there and asked did they have any free Diamond upgrades available. They upgraded me to the fitness room - with a gym inside the room - for free. You don’t get those benefits when booking through a third party.