If, according to you, white has clear advantage because of the passive Bishop on c8, why does he give the pawn d4 at all? He can play 5. ... Bb4+ 6.Nc3.
This line with sacrificing d4 is a main line in chess theory and it is still a debate about its evaluation.
Sure white can retreat with 6.Nc3 (Carlsen won a technical game against Anand in their Wch 2013), but the question is : does white wants to lose tempo retreating, or continuiing development with Bd2?
Are development and attacks on queen and king on centre enough to compensate for the pawn(s)?
There is no clear truth on this line, but if u compare with scandinavian, we are very far away from it...
Similar pawn structure but pawn structure is not everything in chess : there are other pieces than pawns...
If, according to you, white has clear advantage because of the passive Bishop on c8, why does he give the pawn d4 at all? He can play 5. ... Bb4+ 6.Nc3.