Edit: 1st example is also solvable with requestor chests.kovarex wrote:https://www.factorio.com/blog/post/fff-203
2nd example is already solvable with requestor chests (unless you had active providers with repair packs in them; but there's no reason to do that).
3rd example would be solvable with slot filtering, so that only the chosen item can be in a given Storage chest. (Edit 2: Slot filtering for chests would be handy for a lot of other reasons as well tbqh)
My favorite clever use of active v. passive providers was something I did in my 0.12 kilobase for the purpose of automating Steel barrel production for crude oil transport, I wanted an all-bot solution that would add barrels as needed, but not allow for excess barrels to end up in storage. The solution was to use passive providers for filled barrels (so they can never end up in storage), and active providers for emptied barrels (so they would be preferentially taken over newly made barrels, which were also available from a passive provider). This functioned as a logibot analog of mechanical priority (as is frequently done with sideloading), but it can't be extended beyond 1 tier (so no source 1>source 2>source 3, or longer chains of priority). Depending on how these buffer chests are implemented, maybe 2-tier will be possible now, but not beyond that, which can still be a problem (e.g. bot operated fuel priority with Wood, Coal, Solid fuel, and Rocket fuel).