Electrum's focus is speed and simplicity, with low resource usage. It uses remote servers that handle the most complicated parts of the Bitcoin system, and it allows you to recover your wallet from a secret phrase.
Control over your money
This wallet gives you full control over your bitcoins. This means no third party can freeze or lose your funds. You are however still responsible for securing and backing up your wallet.
This wallet uses SPV and random servers from a list. This means little trust in third parties is required when verifying payments. However, it is not as secure as a full node like Bitcoin Core.
The developers of this wallet publish the source code for the client. This means any developer in the world can audit the code. However, you still need to trust developers of this wallet when installing or updating the final software because it was not built deterministically like Bitcoin Core.
This wallet is loaded on mobiles where apps are usually isolated. This provides a good protection against malware, although mobiles are usually easier to steal or lose. Encrypting your mobile and backing up your wallet can reduce that risk.
Prevents spying on your payments
This wallet makes it harder to spy on your balance and payments by rotating addresses. You should still take care to use a new Bitcoin address each time you request payment.
Discloses information to a third party
This service can associate your payments together, log your IP address and know your real identity if you provide personal information like your email, name or banking account.
Tor can be used
This wallet lets you setup and use Tor as a proxy to prevent attackers or Internet service providers from associating your payments with your IP address.
Full control over fees
This wallet gives you full control over fees. This means that this wallet allows changing the fees after funds are sent using RBF or CPFP. This wallet also provides fee suggestions based on current network conditions so that your transactions are confirmed in a timely manner without paying more than you have to.