One might suppose the same configuration that provides low pressure air could also be connected to a shop vac (unless there is a valve in the line). Re-cutting chips implies pocket milling where the chips are very small therefore a small vacuum wand could be inserted fairly close to the cutter without clogging, right ?
I certainly don't take issue with the
convenience of air, that's indisputable. But as others have mentioned, dis-assembly of most older machine tools will always reveal chips that have migrated to unexpected areas. It's a given that these machines have been "cleaned" with compressed air throughout their life.
My smallest lathe has been vacuumed for it's forty-year life (thirty-five years with me) but even so, chips, surprisingly, can be found inside the apron, go figure ! If I'd blown off the chips (even gently) I think that the situation would be worse. But since I've never used compressed air except in clearing chips from a bore, I can't really prove that statement, LOL.
I have five shop vacs distributed throughout the shop, one for the two lathes, one each for the two mills and one each for bandsaw and table saw. These things are very inexpensive and they are small enough to be tucked away underneath most machinery.
Most of mine don't require much maintenance - emptying them a couple of times a year is about average. It's true that the cutting oil coats the filters but it doesn't seem to have any effect on the efficiency -
FWIW, this topic was debated thoroughly in the "Practical Machinist" forum not long ago. With very few exceptions, vacuuming was the preferred method of chip removal.
I guess that it's one of those situations where, as the old American adage goes: "You pays your money and you takes your chances"