This is a position from the main tabia of Catalan Opening:
[FEN "rnbq1rk1/ppp1bppp/4pn2/8/2pP4/5NP1/PP2PPBP/RNBQ1RK1 w - - 0 7"] [StartPly "12"] 1. d4 Nf6 2. c4 e6 3. g3 d5 4. Nf3 Be7 5. Bg2 O-O 6. O-O dxc4
The main move for white is 7. Qc2 with the intention of grabbing a pawn back on c4; however, the same result can be achieved with 7. Qa4.
Why is 7. Qc2 so much more popular? (~10:1 ratio in BigDatabase from Chessbase, with 10065 vs 1186 as of Dec 21, 2019)
Does Qc2 prevent some lines that Qa4 does not? Isn't the idea behind both of them the same?
Reason for asking: I am playing Catalan with both black and white, and study the theory on the materials from Victor Bologan. In the materials, I have, the 7. Qa4 idea is not mentioned; however, I often face it, and wonder if there is any particular idea (or even concrete line) that I should be aware of.