No, you can autoscale EC2s. The point is that you should be able to run all your software without containers, which means that you aren't wasting cpu cycles with container overhead.
Depending on the EC2 instance it also may be cheaper to have a reserved EC2 instance sitting idle rather than paying for capacity reservation and spinning it up every day as the user count goes through its regular wave.
Depending on the EC2 instance it also may be cheaper to have a reserved EC2 instance sitting idle rather than paying for capacity reservation and spinning it up every day as the user count goes through its regular wave.