You’ve answered your own question right there. In that case, you’re better off taking out a secured loan from a traditional bank (despite the aversion some bitcoiners have toward the traditional system), as it proves to be a more reliable option thanks to regulatory oversight - something else bitcoiners aren't exactly fond of, either.

What are the terms for a loan secured by bitcoin? Will the bank pay the client interest for holding their bitcoin? How could it be otherwise, given that bitcoin is an appreciating asset?

Well, now even the banks that used to hate bitcoin are starting to acknowledge this asset and offer related services. That’s how bitcoin is gradually conquering new frontiers.

From the client's perspective, shouldn't this be a matter of indifference? After all, having handed over their assets, they received loan funds in return; consequently, if the bank fails to return the assets, the client has already received the money (making it essentially akin to a sale).

Of course, in the traditional financial system, everything must adhere to the letter of the law, and arbitrary actions by banks are unacceptable; therefore, clear rules would certainly be beneficial in any case.

It’s significant, yet why isn't bitcoin rising on this news? Isn't this a positive news? That’s just how it always goes.

At least in one bank, bitcoin has finally gained tangible "weight".

Yes, that raises concerns about whether BTC price might drop 30%+ during the court process, which is a valid question.
But as for your liquidation point, as reported by CoinDesk, Cointelegraph and Edaily, in case of loan default, BTC can be sold through a process such as court-ordered sale based on the recently amended Civil Execution Rules. I think the Edaily article is using “such as” so that it leaves a chance of there being other ways of asset recovery. But all media reported that its court ordered sale and not through private power of sale. Also since BTC will be held by a registered third party custodian, there is no stage where the bank will have physical/legal possession of BTC, so it wouldnt be able to conduct private power of sale unilaterally either. So the product itself is based on the new civil execution method for collateral recovery and doesn't have an automatic liquidation process like we normally see in the crypto world.

Be careful when receiving any offer from the government that tends to be an opportunity for you through any Bitcoin or crypto initiative, because it is going to benefit them more than you think it will benefit you. Bitcoin could give you more benefits than you may think, and you don't have to go to any centralized authority before you go to achieve your target as needs arise. Just take your time to plan well and avoid taking a government loan, even if it's in Bitcoin.

Is it possible that there will be a third-party care taker of the bitcoin collaterals on that bank? Because the first thing I've thought of that it is the bank that will hold all of those btc collaterals.

It's advisable when taking a loan from our bitcoin, it's best to put the 10% to 30% Loan-To-Value (LTV) ratio.

You don't borrow 70% and above value from the bitcoin you'll give to the bank as the collateral and that's to protect yourself from paying more interest if crash happens to avoid margin call.