I have quite a few of them and tend to agree with others that they are an invaluable gadget for bags. First they tell you whether the bag was with you on your flight regardless of airline. Second, they tell you how long you have to wait for your bag to arrive. For instance if it says 1 km away you know you'll be waiting a little while longer whereas if it says 100m or with you, then you know it's about to come out.
I can vouch for the other AirTag holders not being good. In particular, I got the official Apple AirTag luggage holder for suitcases and about 5 trips in the sucker got eaten up the by the baggage machine at SYD International and that AirTag was lost. Probably your best bet would be to avoid any of those holders and simply stick the AirTag directly inside the bag. That way there is no chance of it getting, "eaten" by the machines. Additionally, if there are airport workers who are weary of their work being "checked" by the AirTags, they won't be able to see it readily.
Just my 2 cents.
-RooFlyer88