Pros
The company offers job stability.
Cons
Project-based maternity relievers are expected to take on and deliver the same workload but with less pay and little to no benefits compared to those employed within the plantilla who are enjoying higher pay and great benefits. Imagine being expected to pick up and master all the work and process within a couple of days/weeks because you are only relieving someone on maternity leave, with little to no support from immediate superiors.