Is Shopify worth the monthly cost?
For almost every store under a few million in revenue, yes. The subscription is trivial next to what it replaces — hosting, security, payment integration and the developer who would maintain them.
What decides it
Where it stops being obvious is at very high volume, where transaction fees on a platform plan start to exceed what a custom build and its team would cost. That is a much later problem than most people plan for.
The part that gets skipped
Shopify handles the parts that are genuinely hard and genuinely regulated: payments, taxes, order records. That is what the subscription is for.
The apps in the Shopify store are where the cost quietly grows. Six at twenty dollars a month is more than the plan.
Most Shopify performance problems are the theme and the images, not Shopify.
Where an app fits
A mobile app sits on top of Shopify rather than replacing it — the catalogue syncs, and checkout stays Shopify’s.