Questions about static meshes and modular building

So I have two questions which are related to static meshes:

  1. When I am creating and building the level (my case mazes), how important is it that I use BSP then delete them and put in Meshes?? I understand the idea of Modular design and blocking out the level but it seems that if the person knows what the exact layout of the level would be, blocking out doesn’t seem so necessary in that scenario.
  2. Is there way for to perfectly align the static meshes automatically? Or an option for it ?

thanks in advance

The way the engine works, BSP does not have as good of performance as static meshes so it’s better to replace it. If you know what you want to do already then you can also go straight to static meshes and not use BSP at all. BSP is convenient because it already has collision and you can build within the editor so it’s faster to make changes and do testing.
For making sure things line up, usually you’d model things so that the dimensions fit to the grid and so you can just use grid snapping. Otherwise, you can also arrange your meshes in your 3D program (at least Maya and 3ds Max can do this) and then export everything to UE4 using the FBX Scene Import which will then allow you to match the positions of where they were:

Ok I understand now, the only 3D program I have is Blender, however some of the static meshes I been using are BSP that I prepared in UE4 and then converted them into static meshes.