I live life for the now instead of waiting for a better one in unsubstantiated afterlife.
This is an excellent question. My answer to this is a massive YES. It has also given me a different attitude to life. Two experiences I had recently (1) my Aunt, a very religious lady in a recent discussion, insisted I shouldn’t tell people how I felt about my enlightenment, ending with her her comment “I know religion is made made” and during the Christmas period I met with a dear friend of mine from Iran and also an Engineer . I was finding it difficult to tell him of my new opinion and the research and time I had put into this. This chap is quite religious and told me I shouldn’t be thinking this way and when I suggested to him that he was treating religion as insurance he said “yes”. This said it all for me. I’m glad I’ve changed.
Well in abstract terms as others have pointed out, life can only be more valuable if it isn't indefinitely extended into some afterlife.
On the other hand, you can also easily not pay attention to your own mortality. I think the loved ones in my life who have died have been a more concrete and immediate illustration of the transient nature not just of life, but of all things. This has done more than the abstract notion that I am mortal, to motivate me to be more present, to leave nothing unsaid, etc.
I think to value life, we must first value our own. I realize there are some people who do not value their own life let alone someone elses. I'm not a psychologist but they must experience a deep running problem. I used to hunt both small and big game long time ago. During one dove season I shot a dove. I picked it up and it wasn't dead yet. That bird looked into my eyes as saying, "why did you kill me? What have I've done to you? I've had a life I've enjoyed just like you do". That was the last time I've ever hunted.
Even if someone's life is not important to you, It is important to that life's owner. Do we have a right to take it? I know this last sentence can lead to another discussion about death penalties. That's another subject of which, I'm for it.
Authoritarian religions, such as the Abrahamic faiths, devalue life in the hear and now. When you're religiously indoctrinated, such as Christianity, you are commanded via scriptures, over and over, to die to yourself -- that you must decrease. You are also taught that this life is just a dress rehearsal for the "real McCoy" in the afterlife. So, with that said: