The following is a personal opinion that is probably shared by nobody.
Whether a pen is used with the cap "posted", depends on the pen, and how much writing I do with it. There is one big difference between a kit pen and a commercial pen, and that is balance.
The difference in the balance of a kit pen and a commercial pen is very noticeable.
50% or more of the weight of a kit pen is in the cap. Add the weight of the post on the end of the pen, and 70% of the weight of the kit pen is waving around in the air above my hand as I write. It makes for an unbalanced pen that I have to grip tighter to control on the paper. The tighter grip is very tiring on the fingers if I write a lot with it.
About 25% of the total weight of a good commercial pen is in the cap, and there is no extra fitting to make the posting possible. That makes for a better balance and a looser grip on a pen that is easier to control on the paper. The looser grip is less tiring to use.