In my opinion Long-term statistics tables should be on a separate database than the main one.
If you have to delete DB for corruption or other problems you’ll loose all your long term statistics with months of precious data!
The database is written and rewritten very frequently so the corruption is not an infrequent event. (at least when using the default SQLite DB)
If the databases are two, however, the last term statistics DB would get written only once an hour when updating statistics, greatly reducing the corruption probability.
Furthermore, by dividing them, it will be possible to delete the normal DB leaving long term statistics intact.
It would be also possible to backup the long term statistics and restore it in case of disaster recovering with ease.
Obviously when using other DB than default (MariaDB, …) two connection should be configured. This way you can optimize DB parameters and virtually use even two separate servers.
I believe that splitting the database will be the best option we have for data integrity.