Hi Gilles,
When you have two routes towards the same destination in your routing table given by two different protocols. e.g. Static route and BGP route. and if you want to choose one route as Active, Route Preference can be used to achieve that. Lowest Preference is give the Highest priority.
When you have two routes towards the same destination in your routing table given by the same protocol. e.g. two static routes and if you want to make one as Active, you can use Route Metric. Lowest Metric is given the Highest priority.