Why should you buy from an AD?

I got bored this weekend and so I sat down and I compared the prices of every Patek that isn’t an Aquanaut or a Nautilus that’s $70,00 or below at retail vs what you can find them for on Chrono24. This basically left me looking at the Calatrava., complications, and Ellipse collections.

Other than 2 variants, the 5205R (green dial) and the Ellipse on the rose gold bracelet it seems every other watch sells for below retail in the grey market. Yes New/unworn and slightly worn.

Now I’m not watch charts and this was a pretty rudimentary version of analysis, but this is what I found. Some of these watches traded between a 5K below and others were 15k to 20k.

I struggle to believe that if you buy three watches from them, (say two complications and one calatrava) that puts you any closer to getting a steel sports watch. so if you really want to steel sports watch, why would you just not buy one grey, even in an inflated market and if you really don’t care about buying a Steel sports watch and you just want those Watches, why would you ever buy them retail?

Is it peace of mind?

This is not intended to be controversial. I only own one Patek, and I got it from an AD and was happy I did. But as I think about adding more to my collection down the road, I struggle to figure out why I should ever buy from an A.D. Especially because I live in the US in a very high sales tax state.

Thoughts?