You can't pick one or another. It's all about scale.<p>When you're small, you usually don't want to commit to e.g. 3-year cloud spend. What if your business doesn't take off? Early on, long-term commits are a liability.<p>At certain scale you're inevitably going a fixed subscription (committed use) in order to get volume discounts. Depending on how high in 7(8)-figures spend territory you are per annum, these NDA'd discounts will be larger than many think.<p>At the same scale you also use commits to protect your business from stockouts during events like holiday season.
You get a TAM (or a team of TAMs) that will help you bypass some standard support procedures and escalate your requests fast. You work with them on capacity planning for the next 1-2 years, etc.