Let's suppose we have a common Scrum team comprised of a frontend developer (one or two), backend developer (one or two), tester, designer. Let's further suppose that we need to estimate a User Story using Planning Poker. How do we do this?
The frontend developer can't estimate the backend part of the work, so they only say "As a fronend developer I forecast that implementing the frontend part of the work will require 2 Story Points." The backend developer more often than not has nothing to say about this estimate because of the lack of expertise in frontend technologies. The other members of the team (tester, designer) have even less expertise in the frontend development so they also don't participate in estimating. Thus the estimation is effectively made by a concrete technician and not by the development team.
Effectively each member only estimates their part of the work.
Planning Poker looks to be more suited for non cross-functional teams, for example, the backend development team (comprised of Java developers) or for the frontend development team (comprised of frontend developers).
What should common teams comprised of common (not having variety of experience) developers do? Can't they be a Scrum team? Frontend developers in my team can't foresee risks related to the highload backend tasks developed by our backend developers. And our backend developers have little knowledge about complexity of modern frontend frameworks (Angular, React, etc).
They can't estimate what they never do - it is clear. If Scrum Master insists on learning to do "team-made" estimates the team just makes them up.