From my understanding, and what I can read from what they said: They're suggesting Bitcoin is not practical for what the current average rate of transactions on other payment networks would require of it, should it even take on a lesser portion of those transactions (eg. X-thousand transactions per second).

It is useful however for a value store. Eg. You can't rightly trade units of gold 50,000 times per second, but it's a good bet that if you buy some and stow it that it will at least hold or even appreciate in value.

Believe it or not, Bitcoin isn't actually transactional these days. A new feature called "replace by fee" was introduced that allows coins that were used in a transaction which is still in queue for processing (hasn't yet been included in block by the miners) to be spent in a different transaction as long as the spender pays a high enough fee to jump to the front of the queue.

Imagine if your visa card took anywhere from 10 minutes with high fees to 30 minutes with "average" fees. It would be fairly annoying to use on an everyday basis.