bitcoind was not explicitly designed for fast querying of address balances or historical transaction searches. While it can be used for that, its primary job is validating and relaying transactions and maintaining the blockchain. Performing these types of queries directly on bitcoind can be slow and resource-intensive, depending on your hardware.

Electrs is optimized for fast queries and can quickly return address balances, transaction histories, etc. This is especially useful when you're interacting with lots of addresses, as is common in applications like wallets that use hierarchical deterministic (HD) key structures. One of the largest advantages of using Electrum or Electrs is its indexing capabilities. bitcoind does not come with a built-in, efficient index for fetching transactions by address.

However, Fulcrum may be more performant.