Just my 2 cents... I became a travel agent in 2019 as Self employee working under a host company. This is very common thing, and a great source of information is at hostagencyreviews.com if you are interested. Very affordable too, and if you have a large network of people, you can be traveling for free!
Unfortunately for me, Covid hit in 2020, and I had to leave the business in 2022. But here are some interesting things I learned.
My host company was part of a larger travel consortium, so as agents we had additional (exclusive) benefits that we could offer to our costumers. For example, on some Royal Caribbean cruises (or any cruise line) we had exclusive rates with additional on board credits. These rates would only be available to anyone under the travel consortium, but not even Royal Caribbean would make these available to the public. Also, the bigger the consortium, the better the benefits/rates. Not all cruises qualify, and some get used and the rates are no longer displayed.
With regards to price changes on cruises. As agent we would get paid after the cruise is completed, however, every month cruise lines would offer additional incentives to sell bookings, and those would be completed and paid sooner or you would get some sort of bonus. So it would be of interest to us as agent to offer you the best rate, and keep the agent present and in communication for your next vacation. We would also not want for you to cancel and rebook directly.
As agents we would also get paid if you booked your next cruise onboard the cruise we sold. So we would definitely encourage you to shop on the cruise for better rate next trip.
On all inclusive type of vacations, we would also have exclusive rates not offered to the public. We would also receive special upgrades for our bookings, or some sort of benefit. So if you wanted the least expensive room, and saw the price on any website, I could usually match the price with some sort of upgrade, or same price for a nicer room plus some upgrade/benefit.
Also on all inclusive type of vacations, we could up-charge, and that extra charge would be ours on top of the commission paid by the provider. This additional fee is never showed to the costumer by the provider. We could also do the opposite, and reduce the overall cost by giving up our commission.
Most top agents I met at a convention from our host company would charge a retainer type of fee upfront in order to work with clients. These agents have great reputation, usually have direct contact with executive vendors (people that can resolve issues quick), and usually work exclusively with high end products. Vendors treat some of these agents like stars.
There are no commission on selling most flights. There were commissions on business/first class international, but I never sold one. Many people use miles/points for these.
Travel agent do travel for free... We would receive all types of offers to go visit hotels, all inclusive, etc, for free. Even if it is not offered to us, most vendors have a backend website for travel agents where we are able to request free stays. Even Disney parks had free days for travel agents (not their families)!
Group travel agents usually travel for free in the group. I meet some many agents that organize travel for groups, that they usually travel for free (some as free "guides"). Every vendor is different, but sell 10 cabins, 1 is free. Book 8 all inclusive rooms, 1 is free. Some of these agents organize church groups, business continue education on a cruise, anything you can think of, and they usually travel for free! On larger groups, they can even split any additional free rooms to reduce the overall cost of each person.
So the are are some clear reasons why you would use a travel agent or agency, and those are the exclusive perks and discounts not offered by big tech, and having someone work for you to make it all happen while having their support. On top of that, they are usually very knowledgeable on the products they sell, and can make big difference in planing activities, layovers, recommendations, and anything related. The negative would be, paying extra for their work (so shop around). Like I said, some agents can up-charge with no disclaimer (not all vendors allow this), or charge that "retainer" fee, but if you are dealing with a 20k river cruise and have multiple flights to deal with in another continent, it might be worth it!