I suppose you could consider it a pawn shop mode; the reason I am describing it as a bank is that its custodial, in that you dont own your btc in cefi, you are giving it to someone else, in defi, you retain primary ownership (unless liquidated) but lose usage#
Typically in crypto loans, you simply repay at the end of the term rather than fixed payments (although of course you can choose to redeem in chunks or only partially redeem it). The oracle problem, is a known issue with oracles that rely on continuous price feeds to monitor liquidations, however there are alternative oracle types that dont rely on feeds, but simply get a price at the time that someone wants it, and typically uses a time weighted average price from multiple markets. which protects you from that, but yes, the reliance of a lot of lending platforms on
Chainlink(which relies on a continuous price feed) is an issue which is much discussed.
I'm not sure which "change to the law" you are referring to. The real "law" in blockchain is the smart contract, you cant change a smart contract once it is deployed. There can be changes to governance certainly, and smart contracts can be governance dependent, (eg rely on the governance to set the interest rate), but again, you pays your money, you takes you risks. If you are referring to analogue law tho how is that going to impact on a smart contract?
Decentralised finance is not regulated by analogue law in any meaningful sense. Yes, countries can have regulations saying "you must not offer crypto loans", and certainly defi protocols often have "terms and conditions" on their website, (typically saying you agree you are 18+, you do not live in a state subject to economic sanctions and that you do not use it for illegal purposes), but if a 12 year old in North Korea used it to take out a loan to buy crack cocaine on the dark web, firstly who is going to know that they are 12, that they are in NK or what purposes they are using the loan for, and secondly even if "they" (who - protcol? government? financial conduct authority) did find that out, what are they going to do?
How do you put code in prison? How do you impose a fine on the blockchain? How do you shut down a decentralised, distributed global network?