I will take that bait, and respond in this manner, brother: with Scripture...
“Do not let your hearts be troubled. You believe in God, believe also in me. My Father's house has many rooms; if that were not so, would I have told you that I am going there to prepare a place for you? And if I go and prepare a place for you, I will come back and take you to be with that you also may be where I am. You know the way to the place where I am going.” Thomas said to him, “Lord, we don't know where you are going, so how can we know the way?” Jesus answered, “I am the Way and the Truth and the Life. No one comes to the Father except through Me. If you really know Me, you will know My Father as well. From now on, you do know Him and have seen Him.” Philip said, “Lord, show us the Father and that will be enough for us.” Jesus answered: “Don't you know Me, Philip, even after I have been among you such a long time? Anyone who has seen Me has seen the Father. How can you say, 'Show us the Father'? Don't you believe that I am in the Father, and that the Father is in Me? The words I say to you I do not speak on my own authority. Rather, it is the Father, living in me, who is doing His work.” John 14:1-10 NIV
I rarely quote out of anything other than the KJV or my Young's Literal Translation, but I figured since your tags are from the NIV, that I would oblige you in that.
Now let's just take a close look here, shall we?
"My Father's house has many rooms; if that were not so, would I have told you that I am going there to prepare a place for you?"
I would say that since heaven is "My Father's house", and since Jesus Himself said "I will come back and take you to be with that you also may be where I am", that pretty much tells me that the saved will indeed one day cross over and see the pearly gates. That is... heaven. So clearly heaven is our destination.
To address another part of your question...
"Jesus answered: “Don't you know Me, Philip, even after I have been among you such a long time? Anyone who has seen Me has seen the Father. How can you say, 'Show us the Father'? Don't you believe that I am in the Father, and that the Father is in Me? The words I say to you I do not speak on my own authority. Rather, it is the Father, living in me, who is doing His work."
I would also say that Jesus Himself has answered it. True, no one alive today has seen the Father, however he has been seen by men. Christ's apostles for starters, to whom He was addressing in the above Scripture.
Finally, I will answer the overall question you posed (at least for myself):
I/We espouse this because it is Scriptural. Meaning it can be easily - and in this case, transparently - deduced as truth on the basis of Scripture alone, with no need to cite outside sources, or church fathers, or Pastor Bob down at the corner church to "prove" it's validity.
I mean no disrespect, but do you believe that Jesus the Christ, the precious Lamb of God, is deity? Or do you, as I hear on occasion, believe that He was just a very wise man? For He was indeed God in the flesh...
May God bless you and keep you...