Bitcoin trading Moving average or expontional moving average

[Galvin]

Right now I'm using EMA since it lines up with MACD on travingview.com. But I have no idea what numbers to use for the fast and slow EMA.  Atm I'm using 10 and 21 since thats what I heard bots use.  So I figure its better to use something that something else is using for more predictability.

But why 10 and 21, why not 30 or 20 or 100 or 50, etc.  Does it matter what chart time is being used.  I been using 1 hour and 15min.