@sindoc The dev’s already said they will not map namespaces to folders, and they have good reasons for this decision.
On the other hand, arbitrary relations between pages can also be specified as attributes.
This technique can easily reproduce the folder structure that you desire. Currently there is no way to display the results, but it seems to be on the queue.
Independently of this, I would love to see the ability to have local Logseq graphs spread over multiple folders. It is a bad design decision IMO to force all Logseq files into one folder and force the user to copy all files into assets (relative links out of assets don’t work). You do not want to re-built your entire filesystem hierarchy in the Logseq folder.
A more natural solution is to go to your budget folder, put all the relevant Logseq files into that folder, and link to them as needed from the outside.
An additional advantage is that you keep all your financial files in one spot, so you can backup and don’t intermix them with your main graph.
It also reduces the risk of accidentally leaking finance info sitting in the same folder with cooking recipes.