It's considered one of the best 5E official adventures, plus it's short, plus Ravenloft is super-popular, plus it's a change of pace from standard fantasy, plus it can be easily dropped into an ongoing homebrew campaign. That might mean that groups who usually use their own world for fantasy games would be willing to make CoS their one exception.It's interesting that Strahd is pretty high in the "completed" rankings. I neither have played nor own it. What do you think makes that adventure more likely to have been completed? is it more fun? Better written? Shorter?
Out of curiosity, are you converting the Paizo APs on the fly or doing more intensive prep?None. Played a bit of LMOP in 2014, tried GMing it in 2015 but only got a couple sessions in before abandoned. About a third to half way through GMing POTA (since Jan 2019). Ran Forge of Fury from TFTYP successfully, and ran a bit of Sunken Citadel but players abandoned it (which also happened first time I attempted Forge of Fury in 5e).
Most of my 5e GMing has been with conversions of OSR modules like Dyson's Delve and non-module Wilderlands of High Fantasy (mostly based off 3e-era WoHF) since early 2015, conversion of the Paizo APs Rise of the Runelords (on book 6, running again today) and Shattered Star (completed) since late 2015, plus 5e Primeval Thule since early 2019.
Looking at my record, WoTC official stuff has been much much less successful than third party. :\ Players regularly abandon official WoTC campaigns, whereas as my Runelords/Shattered Star mash up conversion has run for 108 sessions (109th today), PCs have been Epic-20 level for a year or so now, depending on the PC.
Out of curiosity, are you converting the Paizo APs on the fly or doing more intensive prep?

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.