I would be tempted to get one of these but you can find a GPS + Cellular model on that fat auction site for like 50 bucks less.
This watch model was my “daily driver” until I recently updated to an Apple Watch 6. It still works well (and I have it as a “backup” watch) but lacks some of the newer features (like always on display).
This watch launched in 2018, 3 years ago. It was able to update to WatchOS 8; based on the support life of the Watch 3 this will most likely be able to upgrade next year to WatchOS 9 and then no longer receive updates.
(Look at the release dates vs the End of Life Dates)
If you’re looking for something that’s going to continue to get new features, stay updates for several years, and have some of the additional features (like always on display) this isn’t the watch for you.
The 90 day warranty does not give me the warm fuzzies about buying this refurbished from woot, however, that’s a part of the reason that the watch is cheaper than buying from Apple; after 90 days you’re on your own for any issues you might have (honestly - with the stories I’ve read in multiple different comment sections when these watches come up for sale I’d just buy direct from Apple - it might be more money but you’ll get a 1 year warranty on the device).