It works but won't get you pass of tier 40. Usually that's where the extra speed of the blb will be a must.
Also as an improvement to this guide, I have tested 3 weeks in a round the viability of Zeedmilleniumon. While at 1st I made some pros and cons of the build vs pumpmon, I still had to test how both build could improve after putting a set of king/god runes. After putting runes on most of my digis but cherubi god and zeed (they are 2/5 and 3/5 as far as runes goes) I tested both builds on the higher tiers I can reach, and the results just left me shocked.
While pump build has slightly more dmg and it is easier to use, Zeedmilleniunmon is cheaper as far as cc's goes, I only used 2~3 and this week that I had more time to play it pay off, 3 cc's and so far tier 70 and if I have enough time maybe I could reach a higher tier.
Zeed does better than pump, allows more turns to survive if you play it correctly, but there's a factor of luck here that isn't in pump build, if you're hit there's a chance you'll trigger a digi support (those like demon, ophani and so on) and if the support triggered is one that replaces the protection zeed gives you, then you'll mostly die.
So at the end Zeedmilleniumon > Pumpmon, but it requires thinking 2 or 3 steps ahead, checking you cards, playing it making safe that you'll have another combo in the next turn, and also making sure this time your loop keps doing fine but using only 3 cards instead of 5 which is harder and has luck involved (which can be reduced by playing the right moves).
I could add more to explain how to play with the zeed build but it is harder for me to put it on words, so I'll maybe add a video to explain, but I can't promise it, since it will take me some time now that I'm kinda of busy.