So I see Oda making Luffy with all this destiny crap ... and now he has the "Voice of All Things" just like Roger did. Because of that, they could read the Poneglyphs.
With that parallelism in mind, this means Luffy can now "read" poneglyphs as well. However, this doesn't mean that Robin is insignificant right this instant. With her calculating mind and her past, I guess that instead of doing what the Roger Pirates did they'll do another thing, like use whatever is on Raftel instead of leaving it to another generation like Roger did.
With that parallelism in mind, this means Luffy can now "read" poneglyphs as well. However, this doesn't mean that Robin is insignificant right this instant. With her calculating mind and her past, I guess that instead of doing what the Roger Pirates did they'll do another thing, like use whatever is on Raftel instead of leaving it to another generation like Roger did.