Hector Leano compares the delta and lambda architectures:
Generally, a simple data architecture is preferable to a complex one. Code complexity increases points of failure, requires more compute to run jobs, adds latency, and increases the need for support. As a result, data pipeline performance degrades over time, increasing costs while decreasing productivity as your data engineers spend more time troubleshooting and downstream users wait longer for data refreshes.
Complexity was perceived as a necessary evil for the automated data pipelines feeding business reporting, SQL analytics, and data science because the traditional approach for bringing together batch and streaming data required a lambda architecture. While a lambda architecture can handle large volumes of batch and streaming data, it increases complexity by requiring different code bases for batch and streaming, along with its tendency to cause data loss and corruption. In response to these data reliability issues, the traditional data pipeline architecture adds even more complexity by adding steps like validation, reprocessing for job failures, and manual update & merge.
On the one hand, lambda was always intended to be a compromise architecture based on the tools of the time. On the other hand, take this with as many grains of salt as you need given that the post comes from the primary company responsible for delta.