While both features are admittedly "nice", and look real cool, they are largely un-necessary.
The scallop on the bolt already allows the user to seat a slightly out-of-battery round, so the forward assist often just serves to make a genuine jam, worse. It's redundant, if not counter productive.
But, the military boys got them, so every tubby,basement-dwelling Doofus With A Debit Card (DWADC) just gots to have them too. (this pretty much describes the entire AR/AK upgrade/accessory market).
The dust cover is actually a beneficial feature, but as stated already, in severely dusty environments, it's still nearly useless.
And these severely dusty environments don't exist in the vast majority of this country.
And, of course, in the middle of one of these popularly imagined, domestic, 1000-rd firefights, the dust cover will still be wide open the entire time. Whatcha gonna do THEN ??
As I said, they're nice to have (sorta), and they surely look cool, but their value in the real world is not nearly is high as is generally assumed.
(I never felt even remotely under-gunned with a humble Sport I).
That is all .