The serverless dev experience was delightful! I'd work on a single lambda, or maybe a "stack" of related lambdas, and each was focused and lean. A serverless approach is also probably-necessarily a microservices approach, which removes a lot of complication.

It was in EdTech, so we had students downloading assignments, uploading results (lambda-fronted S3 for blob storage, DynamoDB for data), administrators paging through result, grading things, students uploading images and videos of themselves, administrators reviewing them, many lambdas being triggered by changes to S3 or DynamoDB tables, or SNS messages sent from other lambdas.

I don't think most people would consider it especially bursty, except in the most general sense around midterms and finals, but in truth even a "heavy user" is only hitting APIs every so many seconds at most, and like I said, AWS lambda bills at the millisecond level.