If you try to print a space by using this construction:

     char   emit

You will notice it won't work. Sure, you can also use:

     ."  "

But that isn't too elegant. You can use the built-in constant 'BL' which holds the ASCII-value of a space:

     bl emit

That is much better. But you can achieve the same thing by simply writing:

     space

Which means that if you want to write two spaces you have to write:

     space space

If you want to write ten spaces you either have to repeat the command 'SPACE' ten times or use a DO-LOOP construction, which is a bit cumbersome. Of course, 4tH has a more elegant solution for that:

     10 spaces

Which will output ten spaces. Need I say more?