Those are all good comments and valid when taken together
When we pare back our objectives, which is that a smooth grain next to the pistol fits better, wears better, and releases better, we know that a lining per se is not necessary. It's why rough-out appeals: the hair or grain side of the leather is next to the pistol. Rough-out was used for other reasons that don't concern us pistoleros, too.
The suede linings we have experienced are all chrome tannages. Cheap, thin, strong when thin, and the sueded finish is common. Hides are huge, so cutting economy is outstanding. Whether it's true or not that they collect grit, it certainly is true that they add bulk and that the moulding of the veg face is far less satisfactory.
The solution, if one wants a smooth outer for the holster, is to use two layers of veg layer. If they're both of roughly equal thickness, and the total is about the same as an unlined holster (let's say 10 oz) that means that a pair of 5s m/b used. That has negatives for the maker. So we tend to want to use 8 oz for the face and a very thin liner. The latter is v uncommon in veg cowhide, tho it's what is used to do bullet looping. Very papery and tears like it, too.
Personally I solved this dilemma by using falconry leather. Others have used veg pigskin, which is also excellent. And I put the grain side next to the pistol, for all the reasons I've mentioned; and yet have had buyers wondering why the lining is not sueded.
Perkins at Safariland has always given himself credit for inventing suede lined holster, and John Bianchi ditto. But turnerriver and I can confirm that Heiser was using thin suede linings long before either of those men; I've a Heiser-Keyston "Sportsman" range holster with the thinnest damned suede lining I've ever seen -- and glued not stitched.
So: make up your mind what it is exactly that you'll get from a lining. A luxurious 'feel' of a sueded leather, or a brisk release of the pistol. You'll end up with chrome sueded for the former, and with a grain side veg for the latter.