I just cut mine open to lower the tray and fix the shoddy foothold install that the previous owner installed.
I drilled those two drain holes, used the air compressor in there and blasted out all the water I could. It was probably a good half gallon. then I proceeded to fiberglass right back over the foam a few days later once everything dried enough. I've done three tray refoams and I can tell you the labor involved is not worth the results at all. Foam is also way stronger than the flimsy stock hull and helps keep strength in the rear of the boat where you land from who knows how high up.
I would agree it's not worth it if you use the same foam as before. If you go with polystyrene, it's worth it because it won't waterlog again.