Blocks are great for customer facing products, when you want exactly what the block is done for.

However:

• As always when you use pre-built components, it’s more difficult to customize them later. So if you want flexibility, better create them yourself, or use very simple UI elements.
• Using blocks means that you are dependent on a third-party resources. Use them to imitate them and recreate your own, but don’t copy them
• Simplify your app: if you have to build them from scratch, you will me more tempted to make something simple.
• Teach yourself: creating your own components from scratch can help you gain a deeper understanding of Bubble.io’s capabilities and limitations.

So try to know how Canvas by Airdev or Bubble.io components are built, but try to build something more simpler by yourself.