4c Artifacts wants to assemble value engines and cheap utility artifacts like Candy Trail, Cryogen Relic and The Mind Stone, so Seam Rip can proactively exile one of those cheap permanents (mana value 2 or less) before it generates value. Sheltered by Ghosts gives one of our creatures +1/+0, lifelink and ward 2 while also exiling a problematic permanent, and the ward makes their targeted answers (Perilous Snare, White Auracite, Erode) cost two extra mana, which helps us race through their grindy artifact shell. It does not protect against Day of Judgment, which doesn't target. Trim the top-end Dragons since they're vulnerable to Perilous Snare's exile or Day of Judgment, and we'd rather keep a lower, more resilient curve. Keep the aggressive core since this matchup rewards pressuring their slower setup before their artifact engines take over.