Do you mean do they attract bees? They are known as the 'butterfly bush' as insects with long tongues, like butterflies, are able to reach the nectaries. The poor old honey bee cannot do this, unless it is Buddleiah globosa, of the round orange flowers. Lots of bumble bees have long tongues too, so I would have thought it would be good for them.

I was looking at one on the Crocus website the other day and is advertised as Very Lightly Scented.

It has a slight smell but very sweet. I have some as cut flowers next to a door and the breeze blows in the scent.

Also i have davidii and bees do seem to enjoy it.

I have been and checked my plants. Buzz Red, Lilac and Magenta have a good scent that is fairly honeyed. Buzz Sky Blue has only a faint scent and Buzz Ivory hasn't flowered yet. Buzz plants actually reach a good 5 ft so are not so small as advertised but they are still quite nice. The new Buzz Red is a great colour, a bit like Sugar Plum and Miss Ruby, two more new cultivars.
If you specifically want strong perfume Black Knight is the most powerful but this gets quite large.