ansible just feels a bit slow & cumbersome for simpler setups, so i'm using envsubst for basic templating to see how it feels. It's perhaps telling that something like Rocket.Chat just has `docker-compose up` too: https://docs.rocket.chat/v1/docs/deploy-with-docker-docker-c... and it's annoying that Matrix doesn't have something that simple (especially given Matrix 2.0 has more moving parts serverside: auth + voip server).
That said, the Ansible playbook provides various benefits that you cannot currently get with any other Matrix deployment method. For one, it seems to be the only deployment method that supports hundreds of Matrix and related services which all tie together nicely.
Getting started quickly and easily is an important part, but is not the end. Most people will sooner or later need "that extra service" (bridge, bot, etc.) and it's always a hassle to get it added to a "quick & dirty" deployment.
Using the Ansible playbook, enabling an extra service is usually one extra line of configuration and you're up & running with a deployment that has been battle-tested and improved by hundreds/ thousands of others. You're not alone debugging a hand-made "Synapse worker configuration" or "Matrix Authentication Service" integration - there are many others iterating on the same exact setup.
Another compelling reason to go with the playbook is maintaining your deployment over time - handling major Postgres version upgrades, backups, uninstalling old/deprecated services (to replace them with newer alternatives), etc.
Yes, Ansible can be slow and clunky (and the YAML format is definitely annoying), but it seems like a reasonable tradeoff that provides plenty of benefits.
Disclaimer: I'm the author of the matrix-docker-ansible-deploy (https://github.com/spantaleev/matrix-docker-ansible-deploy) playbook