Integrating TypeScript directly into an HTML file for execution in the browser is indeed an interesting challenge since browsers inherently understand JavaScript and not TypeScript. Fortunately, there are some libraries and tools that can streamline this process. One popular solution is using `ts-loader` with tools like Browserify or Webpack, but since you want to avoid a full build step, you might find it easier to use the TypeScript Playground or libraries like TypeScript‘s `

However, using a CDN for on-the-fly TypeScript compilation does come with some downsides, primarily concerning performance. The compilation step introduces a delay because TypeScript needs to be processed and converted into executable JavaScript before it can run in the browser. This may not be an issue for small scripts, but as your codebase grows, the performance overhead will become more pronounced. That said, for small projects or for quick experimentation, this method can be quite effective. If you want to streamline your local development environment, consider using local development tools like `ts-node` to run TypeScript files without manual compilation, allowing you to see changes immediately without complex setups. There's always a balance between simplicity and performance, so choose the approach that best fits your needs.