One reason for this is that it is stronger relative toy our other cards when you are on the draw compared to say Force Spike which is superior when on the play
Sign in Blood [c]Sign in Blood[/c] is one of the simpler cards on this list, but that doesnt make it any less good
Sure, I can grab some value, like Esper SentinelEsper Sentinel, Professional Face-BreakerProfessional Face-Breaker, or Grim HirelingGrim Hireling, but I'll be damned if I don't grab Gray Merchant of AsphodelGray Merchant of Asphodel or AnathemancerAnathemancer
Shelob, Child of Ungoliant The best spider commander we have
Of course, if youre feeling less charitable, you could also characterize them as being dependent on momentum and bad at playing from behind