If your deck's key engine is a 4cmc commander like Kaalia of the Vast, for example, then you will want to run ramp cards that can get her out faster, which means ramp that is between 0-2cmc so you can cast Kaalia on turn 3 or earlier instead of her usual turn 4
They can be interacted with like any other artifact permanent once on the battlefield
If you only have $40 in your Magic budget, which deck should you buy
Cards like [c]Imperial Seal[/c] and [c]Demonic Tutor[/c] are typical examples
The mind games you can achieve with this card are worth the investment, and the three mana spent to cast it will often net you significantly more advantage than merely exiling an attacking creature
Having access to red cards also means you get access to red removal and red card draw effects, which can help to churn through your deck for the answers you need