There are several ways to do a CA finish that don't leave the surface feeling like a piece of plastic, which it is .... Cyano-Acrylate is an acrylic (plastic) that has a very fast cure time and tends to bond to most things quite fast ... which is what makes it such a super glue. (get it? lol .... that's how they named it)
You can put a very very THIN coat of CA on an item, and it will follow the outside grain of the wood and coat it with a very thin layer. You can then immediately polish it and then clean off the excess polish that has adhered to the grain pattern. This leaves a finish that feels more like the wood, but it can still easily get dirty. To prevent this dirt buildup, you can SEAL the wood by putting a thick coat of CA on the item and then sanding it till the wood is just barely clear of the CA you have applied, and then apply another very thin coat of CA and polish. This time, you'll still get the wood grain feel, but any pores or holes in the wood would be filled and unable to collect dirt and oils from daily use.
Now .... a CA finish is somewhat UV resistant, oil and moisture resistant (seals against moisture loss or infiltration IF YOU SEAL THE ENTIRE BLANK), and can be built up in order to compensate for having over-turned a barrel ... It is also somewhat scratch resistant and can easily be buffed back to crystal clear. The duration of such a finish is measured in decades, if well cared for.
Any oil finish needs to penetrate and be rubbed into the surface .... depending on the oil, the rate at which it evaporates can be different. Some oil finishes need to be replenished or re-applied every 6 - 8 months, such as the oil used to eliminate moisture infiltration in your kitchen cutting boards to prevent food contamination.
Tripoli polish (pronounced triple E) is a wax compound mixed with some very fine abrasives .... the wax provides a surface shell as it is applied and melted into the outer wood fibers. Wax will fade/yellow in an environment with a lot of UV radiation (outdoors or under fluorescent lights, ect ... ) but wax coats are typically thin enough that you can't tell. It does wear off, however, and is not very hard at all (you can scratch through it with a fingernail). It does bind with the outer layers of the wood fibers, though, and gives some protection from moisture and tends to repel oils from fingers ... Many people put a wax finish as their final coat to repel fingerprints from staying on the item. As the finish is typically very very thin, you should still feel the wood grain, but this will wear off and need to be re-applied every 4 - 6 months
You can apply a finish made with epoxy ... or an acrylic made from plastic melted/dissolved in acetone and re-applied in very thin layers ... but either of these would leave you with a plastic coating over the pen.
You can leave a wooden pen barrel un-sealed and unfinished. The natural oils of your hand will then infiltrate the wood and stain it in certain patterns ... this MIGHT be preferred by some people, to be able to feel the wood and see how it changes daily over a long period of time. The oils from the skin, however, can leave a distictive smell and wont discourage bacterial growth ... it could cause the pen barrel to break down over time. Many people don't like to see their pen change like this.
Lastly ... you can use a piece of wood that has been "stabilized". A stabilized wood has been infused with epoxy or other sealants that infiltrate the grain of the wood and strengthen it from within. It also fills and seals voids, if done with that intention. Lastly, it requires no additional preservative that prevents it from breaking down or sealing it from moisture changes .... literally it turns the wood into a modern day fossil - totally encased in a plastic bonding matrix. It can be used to turn materials that you normally could NEVER turn into something that can turn easily ... like punky wood that would fly apart the instant your chisel hit it on the lathe, or dollar bills (shredded dollars) that would also just disintegrate without the epoxy holding it all together.
You could literally take a wisp of cotton and stabilize it and turn it into a pen barrel. You'ld see and feel a lot of plastic, with that, but it would work. However, a solid wood blank that has been stabilized feels like wood. It's a little heavier, will resist oil and moisture infiltration, turns like a solid piece even with voids that were missing from the wood or spots that were rotted (very punky). If you finish such a barrel using tripoli or hut wax, you'ld STILL want to re-apply the finish now and then, but it won't feel like plastic unless you are touching parts that were voids that got filled by the resin.