The role of the TMC is to control the travel policy. Yeah, for those confident booking their own travel, it doesn’t seem to make sense to pay a booking fee when they could do it themselves, completely ignoring that the booking fee covers consolidated invoices, data and analytics on spend, traveller tracking, out of hours support as well as access to discounts and rebates not available if everyone was doing their own thing. If a company wasn’t seeing value in a TMC, they wouldn’t be using one.

And also, some travellers don’t like TMCs because it stops them gaming the system - they can’t always book a BA flight because they want the avios, they cant always book a Hilton/IHG for their reward points and status benefits. It’s not travel expenses going in their BA Premium Amex, earning the next companion voucher.