The use of Buffer before saving to IPFS

I am following an IPFS github example to save to IPFS:

'use strict'

const IPFS = require('ipfs')
const all = require('it-all')

async function main () {
  const node = await IPFS.create()
  const version = await node.version()

  console.log('Version:', version.version)

  for await (const file of await node.add({
    path: 'hello.txt',
    content: Buffer.from('Hello World 101')   //<<<=== why Buffer before assigned to content?
  })) {
    console.log('Added file:', file.path, file.cid.toString())

    const data = Buffer.concat(await all(node.cat(file.cid)))

    console.log('Added file contents:', data.toString())
  }
}

main()

I notice the string is converted to binary with Buffer before saving. Can someone explain the use of Buffer here? What about saving an image or video file?

By default Node.js works with Buffers where use APIs who can be streams, if you works with strings in JavaScript, these works in unicode (utf-8) and these can broke with binary data (for example, an image, a video file, etc).

An easy example to difference strings from Buffers could be compare the size of UTF-8 string, as unicode text (counting by character) and a buffer (counting by byte):

> const str = 'Hello 世界';
undefined
> str.length
8
> const buf = Buffer.from(str, 'utf8');
undefined
> buf.length
12
> buf.toString('hex');
'48656c6c6f7720e4b896e7958c'
> buf.toString('utf8');
'Hello 世界'

In summary, it's a standard work with buffers with APIs like FS, Socket, etc.