Of course, if the bill passes, this will be the last such committee to be necessary, because if future lawmakers wish to know what anyone thinks, they will only need to tap into their personal emails.
But for now, the Joint committee is an example of the legislative process functioning at its best.
Back in the day, Parliament was full of experts and wise men (gendered language sadly deliberate) who came to the Commons after decades of experience in a plethora of sectors.
With the advent of the career politician, that's not true any more, and there's a concern that laws are passed by people who know nothing other than what their party whips briefed them.
The continuing wisdom of the House of Lords (well, continuing for the moment) - eminent retirees from industry, diplomacy, academia and more - allayed these fears to some extent. But when it comes to a bill potentially affecting WhatsApp, one worries that their Lordships aren't entirely, shall we say, with it. In a recent debate about online pornography, one peer referred to the British Museum's collection of "erotic Japanese prints": risqué business...
Which is why the efforts to which the Joint Committee is going are so comforting. The members have given themselves a busy schedule: Virgin Media and Sky, Vodafone and O2. NSPCC and NUJ. Retired judges and current tax fraud investigators. Spies from America and scrutineers from New Zealand. A Danish surveillance specialist and Privacy International.
The fourteen members of the committee - from the MP for Skegness to the Bishop of Chester - are going to be extremely well-informed when they have to make a recommendation to their colleagues.
The snoopers' charter has been much derided. My gut reaction is that the critics are right. But at least our lawmakers are taking the public's concerns seriously and are going to extraordinary lengths to make the right decision.
We often criticise politicians for being out of touch. These ones deserve some credit for trying to get back in.