You can mix queryspec / linq queries with other queries, you don't have to rewrite all your queries. Normally paging is done per page anyway, so it's not something that's always needed. So when you need to skip x rows and then fetch y rows where x & y don't fit in a fixed page setup, you can write the query as queryspec and use the offset/limit combo (or skip/take in a linq query).
The low level API won't get any facilities for this.