It's absolutely significant in at least some of the situations where you'd use this. A friend and I are planning on taking a small sailboat across the atlantic next year and were looking at communication options.

We had decided the normal starlink is just not feasible on a small solar-only boat so this caught my attention. It's still too high though. It would take slightly more power than all the other systems combined if it were DC. With an inverter it pushes it over and there just isn't that much prime panel space on a sailboat.

Iirc the hit from ac/dc conversion is 10-20%? So excluding ac from the equation saves 20-40% power use