Evolutionary advantage of fragrance in flowers, and why are many fragrant flowers tropical?

Factual Questions
1

Pretty much the topic. Understood that some plants have nasty smelling flowers (to humans) that attract specific insects, but by and large most fragrant flowers have pleasing fragrance to humans.

So is a fragrant flower attractive to insects over a similar non-fragrant flower ? (assuming this is the evolutionary advantage)

Also, is there confirmation bias, in thinking that many of the fragrant flowers are tropical ? (Are fragrant flowers as a percentage of all local flowers, the same percent in all places on earth ?)

2

Some plants have evolved flowers with pleasant (to our noses) fragrance, to attract pollinators, mostly but not entirely insects (for example, some birds have a well-developed sense of smell and may pollinate flowers). Size, shape and even color of flowers attract pollinators too.

There are plenty of cold/temperate climate plants with abundantly fragrant blooms including viburnum species, honeysuckle, lilac, some magnolia species etc.