Any decentralized currency that achieves instant (less than a minute) transactions, while remaining without vulnerability, will take off, leaving bitcoin in the dust. Yet there's a good chance that bitcoin might become this currency, or that this currency will not be possible in an ideal way.
Open Transactions as the next layer over bitcoin blockchain will work great.
a) very fast .. under 1 ms
b) does not require transaction in blockchain (OT will use blockchain only for clearing ... 1 transaction daily/weekly/monthly/yearly? .. is enough)
EDIT: it will work even GOVERNMENT ban bitcoin, ... blockchain is your bank / (government can disable new transactions ) but he cannot change history. (already existing transactions)
That's currently the only known method of instant transactions with crypto currencies, and is how Ripple itself works, yet it remains centralized. It can be destroyed, it can become malicious, it is not 100% safe, and won't be largely adopted by bitcoin enthusiasts.
Ripple is excellent example how it will not to work
1. centralized
2. malicious
3. not
100% safe
4. won't be
largely adopted
... :-)
I disagree. I see Ripple as one of bitcoin's biggest threats. Not because it is better, but because it is
worse, but in a convenient way.
All the points you mentioned (except for the last one) are irrelevant for consumers (and small businesses) who just want some convenient and cheap way to use "digital money".
The marketing of the Ripple team so far is impressive, and they try to position themselves in such a way that they seem to pose no threat to bitcoin.
In fact, they're actively trying to warm up the bitcoin community for their project -- they sort of want us to think of Ripple as "another layer on top of bitcoin". Maybe that's how it really is. No objection from me then. But I suspect the Ripple people wouldn't exactly object either in case Ripple manages to take the place of bitcoin as an actual currency and store of value.
tl;dr There's something decidedly disinenginous about the way Ripple markets itself, and I'm not completely sure the people behind it won't try, and perhaps even manage, to become a "bitcoin replacement". Don't underestimate them.