EVLT, phlebectomy under general anesthesia?

You definitely do not need general anesthesia for these procedures. Both can be done in the office setting with local (tumescent) anesthesia, and are very straightforward procedures.
Unfortunately, if the surgeon is employed by a hospital, they can coerce the surgeon to bring you to the operating room so the hospital can make more money off of the procedure. I've seen it happen before.

EVLT and Varicose Veins can be treated very safely and effectively with local / tumescent anesthesia in an outpatient or office based venue. Today, there is no need to undergo general anesthesia or have the procedures done in a surgery. Both general anesthesia and surgery centers add a good deal of cost to the treatments and offer in my opinion no advantages.