Use Unreachable Routes or Firewall

RouterOS Beginner Basics
1

What are the pros and cons of using the firewall vs routes to stop private IPs from being routed outside of your network?

I’m currently using:
/ip route
add disabled=no distance=10 dst-address=10.0.0.0/8 type=unreachable
add disabled=no distance=10 dst-address=172.16.0.0/12 type=unreachable
add disabled=no distance=10 dst-address=192.168.0.0/16 type=unreachable

But was thinking about doing the same idea with the firewall.

2

Firewall: more control and more options, takes more resources
Router: takes fewer resources, can only drop

3

Makes seance. I’ll just keep what I have. Thank you.