I know this question has been brought up in the past on the community and figured, since @Tomer_Noy mentioned internally, I'd share it here.
Starting from R81.20 and in R81.10 JHF 79 and above, an enhancement was added so that for gateways with ISP redundancy, the Management will try to use the secondary interface (and IP) in policy installation if the primary IP is unreachable.
Here is the exact reference:

This doesn’t cover all Management capabilities (such as monitoring and more), but for the “mission critical” policy installation it can be very helpful.
This doesn’t require changing the object’s IP or using DAIP.