I agree with your statement about zoom climbs but they shouldn't be referred to as "best angle" climbs. That's incredibly confusing especially when trying to teach a student what best angle (Vx) climbs are. Discussing the benefits of the zoom climb, like you did, is good but it shouldn't be called Vx (best angle) because that is something different.
Thing is that what will give you your actual best climb angle and avoid a crash is not maintaining best angle speed in the real life examples I gave you.
A bit less focus on the physics and more concern about the reality and actual use of best angle concerning the actual operation of an airplane might be necessary to avoid speaking about matter of very little use when facing an emergency or having to deal with acceleration/deceleration change of flight level in a busy airspace.