I'm going to question the 'beautiful flowers' part of that. From an aesthetic point of view Dandelion flowers don't have a lot going for them. They're aggressively yellow and tend to visually dominate over other plants (and they're extremely efficient at propagating, so if you don't actively control them, they'll quickly become the majority flower) while they're blooming, and the blooms don't even last very long, sometimes less than 24 hours, and a dandelion head that's shed its seeds looks kind-of ugly.

I generally have a very light-touch approach to gardening, but even I draw the line at dandelions. The correct method of dealing with them is a trowel though, not weedkiller.