The Free Plan has a limit of 20 requests per minute that allow you to do up to 4,000 queries per minute. Take into consideration that we count 1 query for each classification or extraction task done by MonkeyLearn.
By using Pipelines, although you still have the same amounts of queries by using all the different classifiers and extractors independently (because you will still need the same amount of text mining tasks), the advantage is less code needed to implement MonkeyLearn, less API overhead and a lot more speed.
Also, take into account that the fastest way to send data to MonkeyLearn is with batch (serialized, not parallel). With batch you can process with a pipeline up to 200 texts with a single request (instead of 1 request = 1 process).