Lol. You must have seen
a lot
You bet it can be very useful for gardens photography
You see this will be f2 - an entry level prime territory with convenience of all in 1 package.
2.8 was never that special until you go past like 50mm. While I prefer primes, and 35 + 85 1.4 is a very good combination you are also constantly swapping with 50 and 135 or even 16-35. 2 bodies is about the limit what you can use at a time unless you have 3 or 4 arms.
Basically not a bad option to have it in the bag as a backup, or in case there is just too much sudden change requiring variety of options.
Besides you don't always need max iso at f1.4. you certainly don't.
My guess is it will sell, and better than canon 28-70mm f2. Price may be the limiting factor though