Cryonics could possibly be used one day for interstellar travel,
but the technique is going to have to be greatly improved upon. Alcor freezes dead people in the hope that advanced genetic engineering and nanotech will be able to bring them back in the future. The already dead body is heavily damaged by their process. The trick is to freeze a living person and bring them back without damage.
As for intergalactic travel, I don't see that happening for a very long time....if ever.
Lee, ( I freeze dead people)