the thing is, PA is only needed for the most important permanent, Eternity (or Pulverizer depending on your draw/duality)
having 6 PAs as dead card in some fights can be the difference between winning or losing, even 4 seems a lot to me (after getting 2 in starting hand vs Ferox)
whereas having tons of Electrum Hourglass is never a dead draw
not only having multiple help switch the focus of permanent controls from your other important permanents, but it is always good having draw +cards per turn (something called 'card advantage' in M:tG)
the only FG that could cause trouble is Seism, but i found out slowrolling your towers should give you plenty of time to stall until you get the PA (and only then you need just 1 for your towers)
i SS the most recent fight vs Seism but i forgot to save the starting hand...it was looking bad, 5 towers, 1 Thorn Carapace and 1 other Permanent, but i played the towers one per turn and luckily got a PA by the third turn
and heres how it end :-
death by graboids ftw!