This might be my biggest pet peeve when people comment on my subdiv ngon posts. It's not a wrong statement, but it's also a pointless one in context of subdiv. Yes, models are all triangles in the end in order for GPUs to render meshes. Nothing you can do will change this fact with the current software and hardware.

But for subdiv, every face is divided into quads before becoming triangles. The distinction is important in understanding the workflow, and knowing that it's all triangles at time of render doesn't change how you work, nor should it because it's an underlying mechanic of 3D in general. It's like saying everyone needs to drink water when discussing whether Coke or Pepsi is better. This is a nothingburger of a statement.

No. If it's shading bad on a curved surface, it's not because of the ngon itself. It's user error and/or lack of problem solving knowledge.

Continuous edge loops are common in modeling, and they can make certain things easier in your model, but they are absolutely not required to make easy edits and I'd argue that more often than not, they make your mesh considerably harder to edit.

Say you have a complex model like an engine block or transmission housing and are asked to make an edit to the model. You need to verify that any continuous loop you add or edit is not going to mess up any other part of your model. This results in a considerable time sink and I highly recommend either terminating the edge on a nearby regular pole, or just cut the edge short with an ngon in a spot that won't hurt smoothing.

I've gotten this one a couple times and it's always confounding how people come to this conclusion. The base mesh triangulation has absolutely no bearing on the subdivided geometry as the resulting topology is categorically different from the base mesh. Refer to "It's all triangles in the end"

For instance, in the base mesh, a quad is made up of two tris. But when subdivided once, that same quad is now 4 separate quads that consist of 8 tris in total. Similarly, a pentagon will be 3 tris in the base mesh but at subdiv 1, that ngon is now 5 quads (10 tris).

Subdivided shading errors are largely a result of density disparity, concavity, or errant non-planar faces.