Any musical instrument is usually a valuable investment, especially if you want it to perform at its best. As such it deserves the effort to help it meet that goal. Any musical instrument deserves to be in a hardshell case when it is not being used. This prevents the chance that it is accidently knocked out the floor or accidently scratched by humans or animals. This is especially true for expensive wood instruments. Also the airing the house may be too dry for the wood. You can easily regulate the humidity in the case.
Above all. It’s better to be safe than sorry. KEEP IT IN ITS CASE when you are not using it.