These sleeves were very useful items. I kept them on my shaft and butt when inserting them into my case because they seemed to add a little extra protection.
If you need nylon sleeves on your shafts to protect them from your case, then you should consider buying a better case, e.g. a JB Rugged. I bought a Cuetec cue, and I took off those sleeves, and I put the sleeves in the Cuetec box, and I put the Cuetec box into storage. I assume at some point I'll throw the Cuetec box away.
Most players I run into try to make packing up their gear as swift as possible: no joint protectors, no wiping off the tip, rather they just unscrew their cues and stuff the pieces into their case, and they are out the door in under a minute.