Long story short, a first-turn Goblin Welder will often lead to a second- or third-turn loss, except without the need to actually attack
Filters can be added from the same facet or another one
Either way, Jeskai commanders usually handle instants and sorceries to maximum effect, and getting a second round of spells for no additional mana investment is really good
15 Teferi, Mage Of Zhalfir You're Playing On My Time Locking down your opponents has never felt better than the original creature version of Teferi, Mage of Zhalfir
If the spell leaves the stack in any other way, or the permanent it becomes leaves the battlefield, it immediately resumes using its normal characteristics
It is a staple in many competitive decks, and pretty awesome that such a powerful card is included in a starter deck