So given that in almost all use cases, you can have 2 panels in series, they should just say “max 2 panels in series”. Simple.
A good product hides complexity from the user with sane defaults and optional advanced configuration. This feels like the same problem.
As it is, panels are gonna produce variable power depending on the weather. Putting interoperability with third-party panels aside, to get the simplicity of "max 2 panels in series", they'd have to either cap the max power on the panel/generator link and dump the excess, or set the limit based on the worst case a customer is likely to encounter. I.e. they're either gonna waste power, or gouge their customers for extra hardware. Neither of that makes sense for an ecological product sold to a price-conscious customer base :).
"Wasting" those 5~10% during severe winter conditions isn't worth splurging on the voltage converter.
Though then selling units that suggest to not run a few hundred volt strings before paralleling instead does sound bad, as the string doesn't need separate fuses rated to many volts DC.