Use grafana application observability with beyla metrics only

Hi,

I am trying to set up application observability.
I see that it is required to set up metrics generation from traces with tempo. This is item3 in the following link: Application Observability | Grafana Cloud

Why is it required if i enable beyla metrics generation from traces.
Additionally i want to be able not to send all traces because i can get rate limited and it costs a lot of money and grafana beyla can already create me metrics from traces.

What do you suggest?

Thanks,