[groundzeros2015]

The “myth” is you can’t use it for a website because if you have multiple requests that need to write they can’t do it concurrently. (They just take turns of course for the milliseconds of write time.)

If you run a transaction with writes for an hour on any database, the data you update will literally be locked. So your example only works if results are independent of the data other programs want to use.

Of course more granularity of locking is better and enables more designs that would not otherwise work. But somewhere you run into the same problem of writers taking turns.