Under the hood of "Tools" Sparrow offers "Sweep Private Key" which is much better option than just importing as it sends all funds controlled by that prv-key to new address from Sparrow's set. Sure, sweeping requires bitcoin transaction to be made, so Sparrow must be connected to do the action.
Yeah, I know it's there, but there are still use-cases for importing single addresses. For example; an old legacy or nested segwit HD wallet with one or two specific addresses that you want to monitor, but you don't need the whole list of addresses that wallet generated, and you don't have multiple hardware wallets to dedicate to each of those seeds.
I've used a ton of different types of addresses for various services here on the forum (lending, escrow, signatures...) that I want available in one wallet that's convenient to access. I've imported most of those into a single wallet on an airgapped machine, and have the public addresses in a watch only wallet on my main computer. Otherwise I would have to restore the seed for each of those if a magic transaction appears or I want to sign a message from one of those addresses. All of those seeds are archived, and by design, inconvenient to pull out of the archives.
Privacy isn't an issue in the scenario above, so there's no reason to not import those addresses into one wallet. I don't intend on reusing them, but they are already out there and it doesn't hurt to to have convenient access to them.
Electrum is really so cool, but sparrow going to be one of those wallets would be an excellent alternative over time.
I see it as the other way around. I was in the habit of recommending Electrum to anyone who's starting their bitcoin journey, but recently I've been recommending Sparrow to newbies. It's more user friendly, and has default features geared to keep new users' information private. As people become more sophisticated and aware of how to use bitcoin privately, Electrum offers it's users a bit more control. When coupled with a self-hosted SPV server, Electrum's privacy features are second to none.