Hello wielkiczarnyafgan, yea, the 30 4k textures are a massive hit on the filesize, but the 6 example maps come with baked lightmaps ofcourse and those also cost 1.3 gb.
You can always remove any unwanted textures or maps if you want 
Since any seamless texture will work, I assume most people will create or use their own textures but for the people who are just beginning with ue4 I wanted to supply a library of seamless textures.
I hope this isnt a problem for you!