People who build and run applications should work in the same team.

Teams should be auto-sufficient. They should have all the skills and tools required to deliver their application independently. As soon as your delivery depends on something outside your team, things start to fall apart.

Teams have different priorities. If you split your experts across teams, who can decide their priority? You'll need a hierarchy of power where the higher you go, the less information they have to make the right decisions. The teams will feel unempowered to make the right decisions themselves.

Ownership and engagement are not shared easily. Your team feels responsible for delivering because they made promises to their customers face-to-face. They are engaged and willing to make it work. Ask the other team who never met your client and were not part of your project to see how they feel concerned.

Building and running an application is complex and can be done in a million ways, from the first line of code to finding bugs in production. You need to find the proper process and tools for each of your teams to be as efficient as possible. If someone who runs applications never talks to someone who makes applications, you won't find that efficiency.