Ether (ETH) is the native token of the Ethereum blockchain, that is, the currency of this network. ETH, similar to Bitcoin, can serve as a medium for everyday transactions. You can exchange Ether for goods and services at the current market value, and the Ethereum blockchain records these transactions, providing the seller with security and no cancellations after your purchase.
Ether is also used to pay fees necessary for the functioning of smart contracts and decentralized applications on the Ethereum network. You can compare the execution of smart contracts on the Ethereum network with a huge cruise ship: if everything is relatively simple in the car - fill it up and go (analogy with Bitcoin), then with Ethereum everything is much more complicated. A cruise ship has many engines and compartments responsible for various mechanisms. Don't forget that cruise ships also have kitchens, dining rooms, gaming and entertainment areas, etc. - all this, like Ethereum, is combined in one place.
Ether is constantly evolving, becoming a unique reserve currency and method of storing funds. Currently, in the DeFi world, Ether is the most common asset used as collateral for many DeFi applications. This in turn ensures security and transparency in this financial system.