It’s bugs. The advantage is bugs. Good bugs!
Of course pollinators is the obvious one- flowers attract bees!
Flowers also give food to adult ladybugs so they can be fruitful and multiply and make larvae that eat the nasty bugs!
This is a celery which is not flowering, but it’s a really good picture of a ladybug.
But the rosemary which is still blooming is just chock full of the spotted ladies which now that tomatoes are starting to go in makes me feel good for their future.
Also sometimes you get a spectacular visitor. Like a dragonfly or damselfly! (How do you tell the difference? No clue!)
Not sure what this guy’s doing here but I’m happy they stopped for a rest so I could take their pic instead of what they normally do, which is buzz about dive bombing me for several minutes.
And yes- I have to pull this bolting cabbage, but I’m holding off til the last second- largely so I can enjoy the bug bounty of nature.
And also because I’m lazy.
The Neanderthal Gardens 
Yup, after all the bad insects do what they will with the young plants, the beneficial insects move in at the end.
I let some of mine go to seed to provide for the following year.
Some people do it for the birds (with some plants).
If it’s not gonna hurt anything I always do it because it helps sort of build up a ladybug reserve early in the season for all the other nasties to come.