Here are some aspects where you can save resources by outsourcing services: administrative costs (rent, taxes, accounting), recruitment and HR processes, management, and education.
Have complete control over the development of your projects. Adjust the team size up or down when you need it without wasting time on on-boarding or off-boarding a specialist.
Bringing a product to market is even faster by saving time on finding the most appropriate technology stack and experience. Agree, it's much more convenient when you just have a task, and someone takes on the whole routine)
No worries about the quality of the specialist's work. The company that outsources some specialists guarantees the specialist's competence and hard and soft skills for successful work with clients.
Look better for clients by operating with more technologies under tight deadlines. You bring in external specialists confidentially and have a better chance of getting positive customer feedback for your marketing strategies.
Put the focus of the HR department on the strategy of developing in-house employees and finding new employees for your core technologies. Small tasks are always better to delegate.