Generally good thinking, but few "real world" notes

A) you first need to run the service to get any customers

B) this might take long

C) you maybe don't want / can't get VC money at this stage

D) you maybe are not the most advanced dev who can properly utilitize s3 from I/O perspective, getting you to higher costs than possible

E) there might be a time period between introducing the service and getting traction which yields enough feedback, so you can start adding more business features

F) when you are burning your own money, you are more senstive to the cost side - which is not ultimately wrong

Just my 2c

they're not mutually exclusive

They kind of are. A one-man shop can only do one thing at once. Either they save costs on data storage, or they spend that time doing something else.

No, pengaru's right. They're not mutually exclusive. For ex: making the site faster and more stable means I spend less time fixing and keeping things running and more time building new features.

But cost optimization doesn't make a site more stable.(Remember the context here)

In fact, adding another component to optimize the cost is adding another point of failure.

Nah. As someone who has gone from a 1 person project to ~10 people and funding, taking the time to tackle problems like this is critical - it frees up an order of magnitude of time later, helps make the product experience smoother, saves you real money that, when you're one person, really can make a difference.

Performance is a feature. In this case, it’s the perf gained by avoiding round trips to S3.

Which could have been gained by.... hosting on AWS.

Which ends up being back to - purely cost optimization of the initial cost optimization.

It seems like the whole product is focusing on cost optimization. I suspect that the OP would be better off making money by doing cost optimizations for third parties.