I have seen so many distributed data storages fail in a multitude of ways that i just dont trust anyone anymore. After 2-3 years they may have ironed out most bugs and i can evaluate again whether i do trust their implementation to store my data safely.
While I can't guarantee there won't be bugs ;-), we have found that building on Postgres has enabled a much higher level of reliability than other time-series databases.
It's also the case that TimescaleDB provides real benefit and scale even in "single-node" form, which allows for traditional primary/replica replication (for fault tolerance / HA / read replicas and scaling), especially when coupled with our native compression.
So we have users storing 100s of billions of rows in hypertables in the non-distributed version of TimescaleDB as well, including in our fully managed cloud service.