Hello dear applicant,

Hope you’re doing well..

yes, you can do post graduation or masters in two different subjects. But not at the same time, otherwise one degree would be invalid.

You can do one after other. And yes, it is useful for some courses. Also, you know, knowledge and education never go waste. It has benefits in specific jobs or fields mostly in teaching.
if you have the capability, ability and capacity to pursue masters twice, go for it. It will give you some benefit for sure and no harm in doing so.

One degree you can pursue regular, other you may do from open along with some job or other things

All the best for your future