The Pros and Cons of Playing for D4

I was aware that these positions after Black Place D5 and Black Place D6, that the computer estimates them very highly for white. I checked relatively recently after my game against Argyndt,. Argyse, from a similar position, not the same position, but a similar one. And the computer was liking it for white. It just said you played D5 and then you play on the queen side A4, B3, 9G3, so on. He didn't go for 97G6 and said he went for a D5 plan, which is much more direct. That was a steal, right?