You also get 137 credit, and breakeven is below 85 (83.63). So almost identical to the naked put at 85
What makes this better than just selling naked put is that, when VST drops, if it only drops to 92, you can actually make a profit from that spread between 100 and 92.5. So, you would be happy when VST drops initially
If you just sell naked put, you will not be able to make any more profit than the inital credit of $150