I intentionally initiated this question with the intent to raise "art identity" awareness among those who do not have the chance to practice in a dojo (and to others as well). While many practitioners may not even be able to practice indoors at home due to insufficient ceiling height to swing a shinai, others may use a gym or empty storage facility, or just plain and simply their own backyard.
In terms of appearance, swinging a shinai or a bokuto in plain clothes may look like it is not more than "someone (dangerously) swinging a stick" while doing it with kendogi on gives a sense of confidence the user may be familiar with what he/she is doing. It also provides the practitioner bonding to the essence of the art, its origin and traditions.
Although a piece of clothing or a uniform will not make you a better artist or sportsperson nor a more consummate kendoka, it will help express and distinguish what you are as an artist than what you are just simply doing.
Kendo-Guide.Com: Thank you for the question. I think you gave us some thought.
If people do not have access to dojo, it is very important for them to have their own official training time. In their official training time, they should start with seiza, mokuso and other training manners. Just to separate it from just suburi exercise.