Regarding battery strap location for hold downs. Bill, your first two photos, RC8Be and TEKNO, illustrate a common hold down flaw. The "D" ring on the end of the strap is positioned at the far side or end of the battery-in both the transverse and lateral examples. That puts all the hold...
Hard case vs. soft side LiPo offer comparable security held in place by a composite battery strap. Regarding Velcro strapping a battery in place as is the current trend, the opportunity to compromise the soft pack over time exists by over-tightening the strap.
Then, of course, there is the...