Pros: Compatible with alpine equipment
Cons: They're not that heavy, but they require the use of heavy alpine gear for going uphill
Trekkers are a good choice if you want to get a taste of the backcountry without going bankrupt. They are a catch-22 type of purchase: if they work for you, you will catch backcountry fever almost immediately and will be scheming on how to sell your trekkers and a) how to budget for a full-on AT setup or b) how to get your telemark skills dialed in so that you're not thrashing around in less-then perfect conditions. So buy used trekkers if possible.