When it was first launched, Google suggestions came with a 'number of results' figure next to them, which disappeared soon after. Google Suggests is for ease of use, rather than for any SEO tactics, so they removed the figures.

The other side to this is the fact that it's easier to optimize for the terms Google Suggest already gives you than to try to make Google suggest the terms you're optimizing for. Use it as keyword research - if you're optimizing a bracelets e-commerce site, you'll see Google suggest 'bracelets for men' and 'bracelets for women' - other queries will produce less obvious results!