There are a lot of considerations. I could literally write 10 pages on it.
In essence:
First. you have sheer size.
1 component is small. 10 component of the same size give you 10x the size.
Then you have LOD balancing - it’s easier on smaller components, but more components = more draw-calls. More draw-calls on a massive map = low FPS.
That said, the largest component possible is impossible to balance correctly for performance.
Then you have adaptation considerations for world composition.
Assume you have an area of 100KM to put into the game. Will you be better off with 100100 tiles of 1km or with approx 1212 tiles of 8km?
Anyway, back to your questions at hand.
Yes you will have issues if you scale the landscape.
You will get spikes and artifacts everywhere including on paint. You are only supposed to touch the Z scale.
And, at best, reduce the scale of X and Y to get more resolution.
There are no Pros or Cons to just having “less components”. It is entirely situational as to what you are attempting to do.
Can your project afford more draw-calls to have more components? Can your project afford loss of detail with less components?
It’s literally a balancing game - of which you have no idea until you have a somewhat finalized scene - or experience.
I would suggest you pick the least amount of components for the overall size in meters you are trying to map, within reason, attempting to keep it to an even number.
below 4km in size per tile, you can pretty much balance any of the component sizes except the largest, so you are less constrained.