What inspired this wish list request?
It's not simple to ask a column whether the checkbox in the column info for Use Thousands Separator is checked. You can set it as part of << set format. You can currently find out how it's set via << get format but only if it's different from the overall Preference under Tables, Use Thousands Separator. If it matches the preference it's just not mentioned by << get format. That had me baffled for a quite a while thinking there was just no way to get it. So you have to check both things and you need to extract it out of the Format() expression returned by <<get format. Not impossible but fiddly and potentially confusing when you don't see it returned at all.
Are there reasons to care? It impacts the character strings you get a list of when you use Summarize and group by a numeric column that is using thousands separators. I ran into this as a bug in some old code that wasn't expecting the possibility that data that was 1000 as a numeric value might show up in the Summarize results as "1000" for one user but for a different user as "1,000". It is just more robust to deal with the numbers and not make assumptions about the string form so I'm not actually using interrogating the column to fix that but the whole experience makes me think it would be worth having a simple way to learn this setting.
Another possibility could be wishing to turn this setting off for some particular scripting then turn it back on again and for that you do want to know what the original setting was.
What is the improvement you would like to see?
A message for a column "<< Get Use Thousands Separator". My request would be to return a simple 1/0 answer to how the checkbox is set for a given column, that is the thing that matches how the data is actually formatted.
Why is this idea important?
This is a small thing and not impossible to do today but could be worth a look. I may make myself a function for this but JMP support suggested I make a wish list item after we boggled over why it was not coming back from <<get format() for a while. This could be a lot more straightforward and similar to how the other checkbox in column info (lock) can be interrogated.