To me Dyson spheres seem decidedly low tech. Why do we think a very advanced alien species would a) even need such an amount of power b) use such a primitve met

To me Dyson spheres seem decidedly low tech. Why do we think a very advanced alien species would a) even need such an amount of power b) use such a primitve method as wrapping a star in solar panels? The only stuff I can imagine needing such energy levels would be wormhole gates or Alcubiere drives. Powering the former with a Dyson sphere might make sense but the latter would have to fit on a ship. The interstellar aliens I find more realistic would be those that just mastered cryo sleep or general AI and built seed ships. We don't really have any way of detecting those, do we?