I like this too! It hearkens back to the old days when Evening jackets with a closed standup collar were uncommon, and nearly all jackets had open collars.

Here are vintage examples of somewhat similiar jackets:





Note that the two men above aren't wearing belts! They were called "dirk belts" at that time and were normally only worn to support a dirk.



That "Balmoral" doublet is nice, but as it costs 540 pounds I think I can live without it.