From my observation nowadays, the flower tactic maximizes both the efficiency value of your attack damage and creates multiple attack timers at a cost of worse damage allocation.
Back then, it was different because you get all three: (1) better efficiency value of attack 2) multiple attack timers 3) better damage allocation) years ago. I am not 100% certain, but with the recent updates, the flower tactic has been nerfed indirectly.
For example:
Let's say you have 10 inf units split into 5 x 2 and you're attacking a 10 enemy inf unit fully-stacked, only 1 out of the 5x2 will receive the full damage of the 10 enemy inf units back then.
Nowadays, it's different because both of the stack 5x2 inf units that you own will get damaged by the 10 enemy inf units due to the splash damage that was adjusted with the recent updates. What does this mean?
The 10 enemy inf units have a better hp% compared to the 5x2 split group of yours. To counter this, if you are using the flower tactic offensively, you must have 33% or more troops than your enemy. This will ensure a guaranteed win than a 50/50 chance.
Furthermore, defensive flower, for some reason do not suffer from this issue. It's okay not to have 33% more if you are using flowers defensively. Meaning, that you can fight someone equal to your number with the flower tactic defensively and come out victorious in that engagement.
The only explanation I can give for why this happens is because most of the time when you are on the offensive with the flower tactic, you will be in enemy territory -- meaning, that other variables will be affecting your damage like building/infrastructure hitpoints and hit rates. To compensate for that, you must have 33% or more troops than your enemy to guarantee a win during that engagement.