What’s the point of making a more portable (I guess you mean lighter?) laptop if the cost is that you make it less portable (because it only works while you’re

What’s the point of making a more portable (I guess you mean lighter?) laptop if the cost is that you make it less portable (because it only works while you’re at home)? I have trouble believing that cost of hypothetical laptop + cost of Mac mini < cost of existing apple laptop. I guess maybe it makes sense if you already have a mac mini?