Hello Katherine C.
Welcome to the SBB Community.
Your conclusion is mistaken.
Even with a Saver Day Pass you could make seat reservations as they are fully optional, no matter the ticket you hold. With a regular point-to-point ticket you can take any train. Thus, point-to-point tickets do not come with a seat assignment either.
Have you seen our blog post on seat reservations in our SBB tips section? It is worth reading it. It also explains situations in which a seat reservation makes sense or is not possible at all.
https://community.sbb-tickets.cc/d/23887-demystifying-seat-reservations-on-swiss-trains-a-comprehensive-guide
As a family with children of 6-15 years of age, I strongly recommend the Swiss Half Fare Card (incl. complimentary Swiss Family Card for the kids) for the parents, or at least the Junior Card for the kids. The latter is available for tourists as well.
https://sbb-tickets.cc/en/tickets-offers/tickets/guests-abroad/swiss-halffare-card.html
https://sbb-tickets.cc/en/tickets-offers/travelcards/children/junior-travelcard.html
Kind regards,
Roland