How REST Apis Make the Difference in programming field?

I am not as good in Blogging as I am in programming.Still I would like to share some of very recent experince with you all as a programmer. Very recently I got a challenging project,in that I had to make shopify public app for a cryptocurrency.
I had to develop an app to make crypto coin accept as a payment gateway.As you all know shopify is restricted platform and we can not inject any code directly in their files and we do not have access to their DB as well.Still they provide REST apis to the developers to override their complete application provided developer should be smart otherwise they will restrict you in apis as well at checkout. I managed to make the custom checkout by bypassing their prebuilt checkout just because of the REST apis however I had to do some tricks achieve that and that is confidential. Whole point is I learnt a lesson from that project that how should we do the development no matter you are developing small or large scale projects.
By converting your function into REST apis it make your code universally accepted.In this modern JS ERA we must need REST apis only. All front-end js frameworks work with REST apis. I would advice to my all juniors that write code in the form of apis so if your application becomes famous in future,you can easiy provide access through REST apis. This is the secure and best method to make the best project.

Thanks!