Many frequent travellers here will tell you that booking directly with the airline, or through a reputable human/bricks and mortar travel agent is well worth the few extra bucks. Yes the online agencies can save you a bit in the short run, but they're never there to help you when things go wrong, and where they are, many of their agents are poorly trained. Going through a call centre or calling some random person in a foreign country is never going to work if yore at the airport and need a problem solved quickly.

For my leisure travel I book directly with the airline(s). For my business travel I book through a human travel agent who knows what I want and need. When I have a problem or a booking that needs changing, I call him, give him the details, and he calls me back within a few minutes to tell me that he has solved everything for me.

I've reached the same conclusion.

Yep, I almost always book directly through the airline after getting a rough idea of what flights are available through one of the big search sites. My wife "saved some time" booking through a search site earlier this year and after a couple months we got an email that our flight had been canceled and their solution was to rebook the outbound leg two days earlier... um. NO.
Luckily they gave a full refund and I rebooked directly with LH. Cost about 25% more and an hour on the phone but seat reservations were "free" the second time around.

until and unless she sees it in her reservation record on the airline website (and, better, prints or screen-shots it), I wouldn't be so quick to make that statement ...

Lessons learned:
Investigate an online company before you pay them a large sum of money, not after there's a problem.

Understand what travel communications actually say, not what you think/assume they say.

Don't "glance through" changes in travel plans - actually read and comprehend them.

what's the over/under on whether there will be another thread on a similar subject before the end of the calendar year?

all too often, what are touted as "lessons learned" tend to become "lessons ignored" and then "lessons archived"