But a coin will either be anonymous or transparent (or the option to choose one or the other per-transaction); no in-between. Is that not a correct statement?
No. For example, here are a few 100% transparent transactions. 
The 2 BTC on the left was mine. Now, which addresses on the right still belong to me? Nobody can tell.
Note that pretty much all wallets are HD nowadays. There is no mixing or other obfuscation trickery at play here, this is just normal default wallet behavior.
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Currently, our fiat transactions, aside from physical cash-to-hand, they are "kind-of" safeguarded by the centralized banking system, in-terms of some level of anonymity.
Hah, for the general public, maybe. They (banks, governments, secret services, paypal, credit card companies, etc) most definitely have all the information they want. All conveniently grouped together in a nice, efficient, centralized database. With fiat, your supposed precious 'privacy' is handed over on a silver plate.
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You can't walk into the bank and ask the teller to show you your neighbor's financial transactions of last week.
With cryptocurrency, you can't either.Quote
Convince me why I shouldn't be concerned about lack of anonymity.
I hope the above picture explains why this is completely infeasible. Still, if you're really paranoid, you might look at Monero's cryptonote protocol. That's 100% anonymity built in right there.