I think the problem more broadly is insisting on using multiple Tor Browsers at the same time, which mainly seems like a gimmick and risking confusion about what activity should be done in which browser.
How often is this really necessary?
The wiki also talks about preferably doing one single instance of anonymous (hopefully) activity, shutting down the Workstation (anon-whonix AppVM), rotating circuits and engaging in the next bout of anonymous activity from the Workstation after a random period of time has elapsed (or even rebooting the gateway entirely beforehand). Even better if one is not running multiple tabs within a single Tor Browser session.
The wiki also talks about having clean snapshots (or AppVMs) for activities & creating special snapshots (or AppVMs) that are only used for special activities e.g. onionshare etc.
What comes out in the docs consistently is that simplicity is next to godliness for maintaining security/anonymity in general and it is user practices/preferences outside of that paradigm that lead to disasters.
That said, users should not be artificially constrained in their choices. Also, those instructions are confusing as it stands in the Tor Browser entry and there are broken/circular links there.
If entropy’s stuff is working nicely, then it would be ideal to use his snapshot in the docs, and fix the steps, because the wiki is currently inadequate in describing this. Nudge, nudge, wink wink @0brand (although over-worked, underpaid, and underappreciated already) 