Upload & Sell: On
dont be cheap w/ your disk space. the catalog is obviously so central to correct operation that it makes sense to have multiple backups. Also, since the catalog is really just a database file (SQLite), it is possible that the TM backup will occur while that file is 'open' and could possibly be in an unstable 'unflushed' state, which, if you needed to use, wouldn't be usable.
So, unless the catalog is HUGE, just let it be and let LR make it's own backup copy.