As the Kingsmills is now the box next to the Press Box, then I assume you're referencing the Press & Journal Lounge!
Occasionally there's no hospitality due to lack of demand, but this is something that's being addressed by offering a different brand of hospitality when the club suspect that could be the case.
You can access the main stand concourses if you are seated there and want to get indoors for a HT Pie and Cuppa. The Sports Bar concourse is fairly underutilised at half time. This is surprising considering it's heated (and has nicer toilets), but despite attempts to redirect people, they seem to want to head for the North End concourse!!
The (what is now) Press and Journal Lounge was trialled under a project called the "Kingsmills Club" a good few seasons back. From memory it was access to the Lounge pre-match, half-time & post-match....including HT Pie & Cuppa, parking, programme and access to pay bar. You also had option to purchase a meal pre-match. However the price point needed to attract sufficient occupancy was so low it made it financially unviable and people weren't spending in the bar, so it wasn't even subsidising it.
This was then tried again slightly differently with a substantial amount spent creating the Sports Bar...which probably still hasn't paid for itself.