It Depends. Don’t do stupid things on purpose.
There are plenty of reasons to avoid giving another role to the Team Lead, but…
It may be unavoidable because of team size or skill set matches. If giving the team lead a role is the only thing that makes sense, do it. If the alternatives aren’t reasonable, give the team lead a role.
The following are a couple reasons not to give the team lead an additional rols.
First, the team lead has a lot to do. Getting down and dirty in the details distracts the team lead from the big picture issues needed to lead the project.
Second, if the team lead does the work, the team doesn’t take ownership. Where possible, the team lead should set the expectation that the team will perform those roles and perform them to an acceptable standard.