I'm generally supportive.
Since the requirement to record every minute of every day has never been enforced under any medium, the potential to have missing information has always existed. WhatsApp is used because US law allows for the content to be encrypted.
It's not a perfect solution but a government attempt to create an In House alternative would just be given to the lowest bidder like capita rather than the likes of Google so I don't have much faith that a sufficient substitute exists.
Greater penalties for missing information are probably best.