While it would be cheaper to deploy your new web app on a cloud VM you configure on your own, or easier to use an intermediate layer like Heroku, AWS allows you to deploy and massively scale with ease for money.
As a developer, AWS skills are currently in high demand, and those with AWS skills can earn big and be snapped up by prestigious organizations.
Common AWS services and their use cases:
VPC - Private network within AWS, EC2s exist within VPCs
EC2 - Elastic compute cloud allows you to create containers to run web applications or other programs
RDS - Relational database service, runs SQL of some sort
Route 53 - Manages DNS queries, can redirect based on region, latency, etc.
Lambda - Run one-off computations instead of using an EC2
S3 - Simple Storage Service, for keeping user data like profile pictures or miscellaneous files
Glacier - Long term data archival service for compliance or backups
CloudWatch - Monitor all AWS services and set up automated actions
Compared to other cloud providers, AWS has the following advantages:
It’s the largest and most mature vendor by a large margin (~1/3 of the market)
Very competitive pricing due to scale
Getting certified with AWS is a popular way to advance your career as a software engineer. The most popular certification to get is AWS Certified Solutions Architect which validates that you can deploy a secure and scalable app on AWS.