Though it is still very early in the list of BT-08 reveals, the much awaited armor digivolutions did seem a little lacklustre. We had several armor digivolutions already revealed, and this includes (probably) the most important one: Magnamon.
Let's start with armor digivolutions. From what we know so far, armor digivolutions have 2 distinctive effects. Firstly, they digivolve for slightly cheaper from their respective rookies. So for example, Flamedramon would cost 2 to digivolve from Veemon, and 3 from any other LV3 Digimons. Second, they have the [Armor Purge] effect, which allows them to sort of de-digivolve to prevent deletion.
This [Armor Purge] effect shares some similarities with some existing effects, such as the EX-01 Mugendramon (purging digivolution cards instead) and the BT-07 DarkKnightmon. These armor digivolutions are therefore not very exciting (yet), so far being only slightly stronger LV4 Digimons with a second life.
But what more can we do with [Armor Purge]?
A Magnamon/Whamon Engine
Magnamon is a natural blocker with a respectable 7000 DP, allowing him to avoid easy removal through a number of effects such as Nidhoggmon, Shoutmon DX, and an inherited Baohuckmon. But that alone will not make him shine.
There is a certain synergy between Magnamon and the Whamon line. Specifically, Whamon can, on play, pull the LV3 digivolution card from Magnamon to be played as a separate Digimon, and then place another blue Digimon (of any level) from your hand under Magnamon as a digivolution card. This will allow you to create a Magnamon with a blue LV6 or LV7 Digimon as his only digivolution card (assuming you do not have a LV2 below Magnamon) hence allowing you to [Armor Purge] into that LV6 or LV7 Digimon. Additionally, since Magnamon has [Blocker] he can slow down the game and becoming quite potent on your opponent's turn, since deleting him would bring an even larger Digimon to the field.
You may even be able to loop the entire engine if another Whamon is put below Magnamon, as Magnamon will be able to purge into a Whamon which can digivolve into KingWhamon in the subsequent turn to redo this engine!
I think such an optimized deck would run KingWhamon for the obvious synergy, and perhaps even Leopardmon to be able to pull out a Magnamon from the digivolution stack.
Will this engine be too memory-expensive to pull off? Or will this engine be meta enough to carry the entire deck? I guess only time will tell once the rest of BT-08 has been revealed.