Both OBrien and Schlansky are worth millions, they can afford to buy the highest quality, most expensive option of just about whatever everyday item they happen to be buying because the price range is from zero to zero in relative terms.
There's a better rule to follow. If you think you need something, buy the cheapest possible version that gets the job done first. If you end up using it enough to wear it out, then buy the best option you can afford. Otherwise you're throwing away cash for something you might not ever end up using. Mostly goes for tools, but also other non-necessities.
I get what you are saying and have done that myself. I bought a cheap tile saw at Harbor Freight, retiled a couple rooms in my home, then gave the saw to a neighbor who did the same. Spending more on that would have been a waste especially since it's not something I was keeping.
A trimmer, on the other hand, is something that I handle every week. It's something that takes up space inside my home. The trimmer they are talking about is around $35 and the cheap version is probably $10. There are times when going for the nicer option is money well spent if using it is a nicer experience even if it does exactly the same thing as the cheap version.
Now if the trimmer were $350, that would probably be a hard pass. But $35? That's fine.
There's a better rule to follow. If you think you need something, buy the cheapest possible version that gets the job done first. If you end up using it enough to wear it out, then buy the best option you can afford. Otherwise you're throwing away cash for something you might not ever end up using. Mostly goes for tools, but also other non-necessities.