Electrum Personal Server is an implementation of the Electrum wallet server protocol that allows users to point their Electrum wallet at their own full node. It is compatible resource-saving features like pruning, blocksonly and disabled txindex. It is much less resource-intensive than other Electrum servers because it only stores the user's own addresses, instead of every address that was ever used. As such it makes tradeoffs, namely losing Electrum's "instant on" feature.
Full node wallets are important in bitcoin because they are an big part of what makes the system be trustless. No longer do people have to trust a financial institution like a bank or paypal, they can run software on their own computers. If bitcoin is digital gold, then a full node wallet is your own personal goldsmith who checks for you that received payments are genuine. You wouldn't accept large amounts of cash or gold coins without checking they are actually genuine, the same applies for bitcoin.
Full node wallets are also important for privacy. Using Electrum under default configuration requires it to send all your bitcoin addresses to some server. That server can then easily spy on you. Full node wallets like Electrum Personal Server would download the entire blockchain and scan it for the user's own addresses, and therefore don't reveal to anyone else which bitcoin addresses they are interested in.
Right now using Electrum Personal Server is the easiest way to use a hardware wallet backed by your own full node. It is very lightweight, being a small python script that barely uses any CPU or RAM; much less than the full node it's connected to. Hopefully Electrum Personal Server can be part of the solution in putting full node wallets into the hands of as many people as possible.
The project is now in beta release: https://github.com/chris-belcher/electrum-personal-server
It now has all the essential features to make it practical for use; Merkle proofs, deterministic wallets, bech32 addresses, SSL, Core's multi-wallet support. Along with the features that were in the alpha release of tracking new transactions, confirmations, block headers, importing addresses.