Comment by kioleanu
Yes, that makes sense, we don’t allow people to connect to our databases directly either, and in any case the systems should be built so they are separated, it’s good architecture.
I was very much more intrigued about the statement that data can’t be easily/legally shared within the same agency
It's to avoid corruption.
I worked for the equivalent of the IRS for two month in my country (student job basically). When people asked for a deferred payment, i could accept it if it was the first time, but when they asked for a deffered payment the second time, or for reduced taxes (recent job loss, loss of a house or big events like this), i had the mean to verify who the person asking for this was, but not the mean to approve it.
I verified the information and filled a form, then asked for approval. The person approving had no idea who the person asking was (he had no access to the tool i used to match the internal ID to an actual person), but had the form i filled, and approved of the deferred payment/reduced taxes without any knowledge of who asked. Also i did not know who that person was, and he did not know who i was.
All of that is not very effective, but it reduces the risk of corruption from civil servants: you either have limited information, or limited power (this isn't the case with mayor or other elected officials though).