The rarity of bitbars is rather void since it can be easily divided. I can trade 0.0001 BTB just fine. But so can I trade 1000 BTC. With digital currencies, the actual amount doesn't really mean anything, only the value it represents. If I have $10000 in coins, yeah I'd want to consolidate that into either bills or maybe gold, simply to save space. No such problem exists with BTC.

A point can be made for having a separate crypto currency as a backup to store funds in, in case BTC fails. But there's no reason why this should be BTB. Almost all alt-coins share the same basic principles with BTC, the most significant difference typically being the use of scrypt instead of sha-256. Something that would cause BTC to fail will probably have a similar effect on other alt-coins (unless a sha-256 weakness is found that doesn't exist in scrypt).

Finally, with BTC being the only currency that is close to being somewhat accepted by merchants and all other currencies having their value expressed in BTC, a price-crash of BTC will probably take down alt-coins as well. Just look at the LTC exchange rate after BTC had a mini-crash following the news of Mt.Gox accounts in the US being seized: LTC had a similar, if not bigger crash.

Right now, there is no real point in consolidating money in an alternative coin. They're fun to mine and (day)trade, but practical use is very limited. Bitbar is no exception. And its rarity is just a play of numbers, it's no more rare or common than any other coin if you consider that crypto currency is dividable into extremely small parts.