I think if multiple rebuys are allowed it is a no brainer to do the add on.
But its either or in this scenario. Everyone is good at different types of
poker games even different holdem types. I'm really good at short stack so having two opportunities to do it would suit my style. Its pretty tight play.
It loosens up ur play a bit not scared to go allin with cards cause u got a second chance not condoning J10 allins but JJ allin is less scary. If you like to bet a lot and
bluff or just like calling a lot having a big stack would do it.
I hate multiple rebuy tourneys... a lot of stupid play goes on so I usually wait till the break to buyin but in this scenario. I would play from the start. There so many bad beats that can happen and personally having that second chance is invaluable in poker. Even the biggest stack can get crushed with bad luck.
My advise... if ur confident of short stack play or play super tight do the rebuy thing. If u don't regularly last 30+ min as last place umm or uncomfortable when blinds get pricey go addon. Regardless u can't go wrong its preference if only one rebuy is allowed... main thing is to play good.