The same group of Disney trip advisers, advises that if you're going to get No Expiry tickets to get them with 10 days and the Water Parks & More option added on, which costs around $696. This gives you up to 20 days of entry.
If you divide it out that way, it's only $35/entry to whichever option.
2 - 5 Day tickets with WP&M would cost $692, and you would only be able to use the admissions on that particular trip.
The combinations with these tickets are endless. Let's say a family takes a trip to Disney every year. They do 5 days in the regular parks and 2 days in a Water Park.
Trip 1: Use 5 days and 2 WP off No Expiry tickets ($696)
Trip 2: Use 5 days and 2 WP off No Expiry (no added ticket cost)
Trip 3: Buy 5 day ticket ($285) and 2 WP off No Expiry
Trip 4: Buy 5 day ticket ($285) and 2 WP off No Expiry
Trip 5: Buy 5 day ticket ($285) and 2 WP off No Expiry
Total: $1551
Trips 1-5: Buy 5 day tickets with WP&M option - $346x5=$1730
That's a savings of almost $200/person.
Basically, you're looking at costs in the long run, and it depends on your touring habits. Even if someone used all their regular park admissions in a single trip, they could potentially ration out their WP&M admissions out over the next 10.
Actually...Mousesavers has 10 day + PH + WP&M listed at $423 right now, which is a steal.
It is possible that the new Fastpass+ experience could be making it so it doesn't make since for people to "ration" tickets in that manner anymore though, which is why it would make sense for Disney to put them on "sale" so they can make money off them now, before discontinuing their convenience.