[OldRestorer]

For me,
I like a nice clean inside. I also like it to be original looking so not shellac or shiny finish. I just brush it out, give it a good cleaning or even a #0000 wool rubbing and sometimes stain it. Some cabinets are more unfinished than others with rough cut wood and imperfections so I feel that they will catch and hold more dust and dirt. Those cabinets I will give a sanding.
In the end, it is your cabinet and if you want it looking beautious inside then go for it. It will definitely make it cleaner and easier to keep clean.

Kirk