New Beanz

I suppose that is to buff the Admiral Navy Beans. Being a 1/1 makes them pretty fragile. (Plus, if the enemy zombie don't have any amphibious zombies you hit them for 3 instead of for just 1.

I don't know, I would use it that way.

I would usually decide to use it on a black eyed pea or pleurodon to go beyond the 3/3 mark. If they soft-wipe (chickening/weedspray) you loose your shroom and your admiral. thats bad luck. in either case your would have lost 2 cards though and if your are left with a 5/6 black eyed pea or a 3/3 admiral doesn´t make much difference in the end to be honest. Especially if your consider the following;

if the have a spotremoval and they have the decision to play it on a 1/1 with huge damage potential or a 4/5 that will get a buff if you remove the 1/1 they actually have a tough decision to make. Beans have the pretty obvious weakness that making decisions against them is usually pretty easy. remove the admiral.

growshroom and fertilizer on something thats not the default priority can make decisions harder. and forcing opponents to make harder decisions as they expect is usually a fairly well strategy to bait them into making mistakes.

also; I considered playing 4 growshrooms but I think the flexibility with 2 fertilize is better because so many people play smash and you could , in theory, fertilize a 2 atk plant out of range of most removal he got

I think especially aggressive-oriented decks profit a lot from this. I realize that it is fun to totally overkill someone with a single, immense zombie or plant but distributing power amongst mutliple targets makes decks much more resilient against low-cost removals and especially bounce effects.