Wondering how useful people find them.
Only really useful if you start with them. Early game, mines are far more useful. I did a few test runs, and I've found it takes around 10 minutes (or 580 ticks of the ingame timer) to generate 20 seedlings with a dyson. The practical effect of this is that in game, you're going to be in your mid to late game on most maps by the time planting a flower on a planet has generated you enough supers to make a difference. Factoring in time to find a flower, move the flower to a useful planet, etc, it'll likely be more like 15-20 minutes before you get a decent number of super-seedlings. The 10 hour achievement estimates it will take you an average of 24 minutes to complete a mission. 30-40 minutes is usual for a mission.
If you start with a super dyson, the super seedlings are very useful for taking out tough planets, stopping early enemy colonisations. With a couple super seedlings you can take an enemy's planet with three or four dysons and maybe double your production capacity early game. You can't do that with a mine.
So, early mission, you won't get enough super seedlings for your purposes. If you plant a flower mine, especially on a developed planet, it will give you the ability to fight off 20-40 enemy seedlings without much difficulty quickly, which is very useful in the mid game. If you plant a flower on a dyson tree, by the time it gives you a decent number of super seedlings you'll be throwing around 60-80 armies of troops, and quite likely moving far away from the super seedling planets, making it hard to use them to reinforce your army.
So, you just throw around huge numbers of troops to overwhelm everyone, and while you know that superseedlings are probably helping a little bit. I haven't noticed any differences from armies with super seedlings in and armies without.
It's a big flaw. Superseedlings are very useful early game, sorta useful midgame, and useless late game. Mines are sorta useful early to mid game, and fairly useless late game, due to the distances. You get mines late early game, and you get super seedlings late mid game, when they're becoming useless. Unless you're very lucky.
Who uses them outside of levels where they are already present at the beginning?
Do you ever put any effort into creating them?
I use them, but I've never found them especially useful. I personally enjoy the sense of power that super seedlings give you, so I purposely colonise weak planets for the flowers, so I can plant them on good planets. But, I haven't noticed any actual benefit from that.
