A final point would be that it isn't just based around the family being taken care of etc. but also the topic's title , i.e they (Pentangeli family) would keep their honor. If Frank had gone through with breaking Omerta, his family would be forever thought of as disgraceful and it would leave a infinate effect on his family's name for all the years to come. At least this way he could preserve the honor of his family's name, which I'm sure to him was more important (or as)as the financial aspect

Pippi

"Dreams come true. Without that possibility, nature would not incite us to have them. "