Why do arabics use numbers in words/text?

example:
http://www.arabsounds.nl/lyrics/index.ph...

it's very simple. The arabic alphabet has sounds that the latin alphabet hasnt.
When persons that have arabic as their mother tongue need to write arabic with for example english sounds, they dont find the correct letters for it, so...putting numbers they are showing to another persons that know arabic too, the sound of the words,
For example the word habibi (丨亘賷亘賷) means my love, has to be pronounced as a "h" from the throat, but as english and most langs hasnt it, arab pple write it 7abibi. ( 7 = 丨 )
Different sounds have different letters. ( 毓 = 3 ) and there are another ones.

the numbers stand for a kind of sound. also because it can never be compleatly translated. only someone who spoke arabic would understand.

There are some vocal letters in Arabic that don't exist in English. Some people write Arabic using Latin letters. This approach started with applications that don't support arabic language. However, in order to put those sounds they started to put digits to represent those non existing sounds.

To add to that,

2 is a glottal stop (like when people miss out the T's ib butter and water, they become bu2er and wa2er)

because it looks like the sign for the glottal stop but backwards

and 3 looks 3in backwards