What standing seam actually is
Standing seam is a metal roofing system of vertical panels (typically 12, 16, or 18 inches wide) joined by raised seams that run from ridge to eave. The fasteners (clips) live under the seam, hidden, and allow the panel to expand and contract with temperature swings without buckling. Nothing pierces the weather plane.
Substrates are Galvalume steel (the workhorse, 24-ga is the residential standard), aluminum (the coastal upgrade, fully corrosion-proof), or copper (the heirloom option). Topcoats are baked-on PVDF (Kynar 500 or Hylar 5000) in 30+ standard colors and a finish warranty that runs 30–40 years.

