I was thinking it had to be one simulatious disconnecting means.
As long as the switches are 'grouped' it is no problem.
I have seen weatherproof boxes full
of condensation inside walk-ins.
Yes that is a common problem and it is caused by failing to comply with 300.7(A)
300.7 Raceways Exposed to Different Temperatures.
(A) Sealing. Where portions of a cable raceway or sleeve are known to be subjected to different temperatures and where condensation is known to be a problem, as in cold storage areas of buildings or where passing from the interior to the exterior of a building, the raceway or sleeve shall be filled with an approved material to prevent the circulation of warm air to a colder section of the raceway or sleeve. An explosionproof seal shall not be required for this purpose.
If 300.7 is ignored you will get water.
Is there any reason not to use conventional 4S boxes?
No not really.
For my work it is usually a customer requirement.
But it is not a problem if you follow 300.7 and make a small drain hole in the box all is good.
Just trimming a notch in the covers gasket at the bottom is enough to make sure the box does not fill with water.