One big advantage is that you don't have a wave you have to sync with (Which is why DC is used for connection between grids). One of the harder parts of AC gri

One big advantage is that you don't have a wave you have to sync with (Which is why DC is used for connection between grids). One of the harder parts of AC grid management is that every generator on the grid has a timing component to make sure it's producing power in the same waveform as the grid. It's not enough to produce AC at 60hz, if that 60hz is misaligned then you generator turns into a load on the grid. It also means that if 2 grids aren't in sync, they can't connect (even if they are both 60hz) without some expensive equipment to sync the waveform. A 60hz grid cannot connect with a 50hz grid without a DC phase.