You just opened a can of worms in my head.... here goes...
1. If you feel that you need justification to vlog (aka views and subs) than don't even bother. People can and will pick up on that quickly.
2. You will be the 26,385th vlogger on YouTube, so don't expect to be an overnight success.
3. For whatever reason, you whacko kids love watching each other putt around on your sewing machines, so yes, having a 250R is a good thing on YouTube.
Bottom line: Vlog to create memories for your future. Forget about numbers, subs, views.... it's all meaningless anyway. I still enjoy watching vids I put up 3 years ago, it just brings back a time in my life I will never get back, and that to me is that greatest joy in vlogging.