In YDB with block 4+2 erasure coding, you need half the disk space compared to mirror-3-dc schema. Meanwhile CPU usage is just a little bit higher, thus in high throughput tests mirror-3-dc wins. Indeed as mentioned in the post there might be a tail latency win in latency runs, but if your task is throughput with a reasonable latencies, replication might be a better choice.
I expect it to save a lot of CPU by only needing 1/3x of compactions. You might want to do a benchmark on that ;). An example is quickwit (building inverted indexes is very expensive).