There's nothing specific to read about it, just plenty of anecdotal evidence. People use connection pools because connecting to _remote_ databases is slow. SQLite _is not remote_. It's _in-process_ and _fast_. Any connection-pool _adds_ to the amount of work needed to get an SQLite instance going.
It's _conceivable_ that pooling _might_ speed it up _just a tad_ for databases with _very large schemas_ because parsing the schema (which is not done at open-time, but when the schema is first needed) can be "slow" (maybe even several whole milliseconds!).
There's nothing specific to read about it, just plenty of anecdotal evidence. People use connection pools because connecting to _remote_ databases is slow. SQLite _is not remote_. It's _in-process_ and _fast_. Any connection-pool _adds_ to the amount of work needed to get an SQLite instance going.
It's _conceivable_ that pooling _might_ speed it up _just a tad_ for databases with _very large schemas_ because parsing the schema (which is not done at open-time, but when the schema is first needed) can be "slow" (maybe even several whole milliseconds!).