It's only more efficient when the ratio in orbits is around 12 or higher, and then you have to go even higher than that to get more efficient, and takes at least twice as long to complete the transfer.
I'm not sure there's even such a ratio in KSP, even Moho to Jool is less than that.
So you'd need to be in a very artificial scenario for it to be more efficient, and the extra time would be tedious (even at full warp) compared to a regular transfer.
It's only more efficient when the ratio in orbits is around 12 or higher, and then you have to go even higher than that to get more efficient, and takes at least twice as long to complete the transfer.
I'm not sure there's even such a ratio in KSP, even Moho to Jool is less than that.
So you'd need to be in a very artificial scenario for it to be more efficient, and the extra time would be tedious (even at full warp) compared to a regular transfer.