Of the three decks on the teaching app, this one was most challenging for me to get used to. Probably because Angemon & Angewomon are not in on the app yet and they might be integral.
I still don't get Holy Flame, what does Security Check -3 entail? Sorrow blue is so much better!
Seraphimon can take out any Digimon one on one while attacking due to his -4000 DP effect (-5000 if you evolved from MagnaAngemon). This effect can also be use on the side while breaking a shield, how ever it can't be used defensively or on shield Digimon. So it can break a shield and destroy a rookie or champion level when ever it attacks. This is useful in clearing out the battle area.
Heaven's Charm can also -2000 DP, so it can knockout an Agumon/Gabumon/Gomamon or level the playing field while attacking her DP Digimon.
Takeru's effect when stacked can make sure your opponent pays heavily for breaking a shield (+2000 DP per Takeru) and again helps clearing out the battle area.
Side note: Interesting that they used Seraphimon's newer tri design on his card and his older design in the 7 Heavens card. I personally prefer the newer helmet and wings.