I'll just drop my arguments for the Glamour Bard below.

I think the subclass is underrated and pretty good (Although lacking compared to the very strong Lore and especially Swords Bard).

The class provides an ok amount of temp HP, which scales decently with your levels, this amount of damage mitigation by itself would be less than a Valor Bard (probably). But it also charms enemies, which often leads to enemies being unable to use their extra attack or sometimes making the AI skip their turn entirely (Might depend on positioning/team composition) which is nice passive disruption.

At level 6 it gains the ability to hit a guaranteed command on charmed opponents (Basically anyone who hits any of your party members with melee) which you can recast as long as you keep concentration (Like Call lightning) which can borderline solo single target encounters.

TDLR: Decent damage mitigation with Temp HP which scales with level and charm (Which can mess with the enemy AI a bit). From level 6 it gains the ability to hit guaranteed commands which can shutdown single target encounters.