There is another way. We should know that we can override the html template via RequireJS. We don't need to create a custom theme. In your custom module, create a requirejs-config.js:
app/code/{Vendor}/{Module_Name}/view/frontend/requirejs-config.js
var config = { map: { '*': { 'Magento_Checkout/template/minicart/content.html': 'Vendor_ModuleName/template/minicart/content.html' } } };