Blockchain oracles act as intermediaries between the distributed ledger and the physical world. It's a piece of software that links the blockchain to other data stores and networks like the web, sensors, and more.

You pointed it right. Besides softwares , oracles can be hardwares too like sensors ( as you mentioned) which can be used for multiple purposes like weather , polls etc.

Oracles are a vital component in expanding the scope of blockchain's applications.

Yes that's right . You have mentioned multiple use cases of oracles w.r.t blockchains . So oracles have diversified the scope of blockchain's and made increased its interoperability as well.

security and dependability, they can be more difficult and expensive to set up than their software counterparts.

I do agree with your opinion. They may be having a steep learning curve compared to software oracles.

a decentralized oracle would allow you to tap into a web of disparate data sources to obtain the most trustworthy market information possible.

Decentralized oracles rely on a distributed network of data providers to add information to the blockchain, making them more secure and reliable than centralized oracles.

Good luck