Vue.js components capitalized

It's just a convention to differentiate between the component constructor/definition (capitalised) and the component instances.

It's a common convention that classes are capitalised but instances of a class are not:

const user = new User()

From what I have seen and used, vuejs doesn't mind your component files', component names' case.

Example:

// HelloWorld.vue   
export default {
  data () {
    return {
      msg: 'Hello'
    }
  }
}

if used in say App.vue like:

//App.vue
<template>
  <HelloWorld></HelloWorld>
  <hello-world><hello-world>
</template>
 
import HelloWorld from 'path/to/HelloWorld' //adding .vue is optional

export default {
  components: {
    HelloWorld
  }
}

There would be absolutely no negative consequences, vuejs doesn't enforce W3C standards

Note that Vue does not enforce the W3C rules for custom tag names (all-lowercase, must contain a hyphen) though following this convention is considered good practice.

source

So you can use an imported component in kebab-case or camelCase vuejs internally checks for it and would render the component the same way.