Hello,
I was able to reproduce the scenario from your description regarding the Cloud Tasks API and the Cloud Scheduler API. You are correct.
I then did some research and found out that the new user interface (UI) uses the Cloud Tasks API. Although the migration to Cloud Tasks is not mandatory right now, the API will need to be enabled in anticipation. This is part of the path to the eventual adoption of Cloud Tasks.
You’ve stated that Cloud Tasks are missing some features that are present in TaskQueue such as transactional tasks and that that pricing would be a point not to use it. This is good feedback and I encourage you to contribute a feature
request to describe your ideas.
I hope this did not cause inconvenience on your part and if you have any related questions about this, you may post again.