The MN has also installed Aster in Sylver A43, A50 and A70 VLS launchers in frigates, destroyers and other ships (non-flat tops). As I asked before, why not put ESSM in a VLS for the most important ship in the USN? The benefits are quicker launch times, 360 engagement and ripple fire capable. Why not have that instead of antiquated box launchers on a $15 billion warship?
There is no available article on the reasoning behind the use of Mk29 ESSM launcher in USN flat tops. But I can wager that it has specific considerations on why that is so. I already mentioned my speculations that it could be that 1) between a VLS and Mk29 launching system the latter provides faster and more direct path for the ESSM against incoming supersonic sea-skimming anti-ship missiles, and 2) the horizontal flight profile of the Mk29 launched ESSM might be safer for the planes taking off and landing on the carrier.
Also note that the SEA RAM point defense missiles is also horizontally positioned. So I think horizontal installation of anti-ship missiles provide the most direct path to intercepting anti-ship missiles at medium and close ranges.
Regarding, 360 degrees coverage of VLS launched missiles, I do not dispute that. In fact, almost all USN ships aside from flat tops are using VLS launchers for ESSM and other air defense missiles. But the Mk29 ESSM launchers in US flat tops are placed on both sides of their flat tops ensuring 360 coverage.