It could be a film designed to do slides (in which case you do need the extra Dmax); it could also be a film designed to do copy work (like the late Tech Pan, which could build an impressive contrast), but I see nothing to this effect in the press release.
Taken from our press release:

"SILVERMAX is coated onto clear triacetate and can be reversal processed"

So, yes, this is ofcourse one of the reasons for the extra silver and DMAX.
We tried to make a film for good negative and reversal processing.

Mirko