I don't think anyone who has a problem with Electron is going to rejoice at the option of a browser window instead. Typical Electron usage is problematic because it is a browser.
But Postage sounds like it might be the rare Electron app that is actually sensible.
If you're open minded, you may want to read this: https://github.com/workflowproducts/postage/blob/master/Fact...
Also, postage has a webserver mode that is simple to install (configure-make-install) and it does not use Electron. You just use a browser window.