praise, extol
襃 centers on expressing high approval: praising someone or extolling their virtues. Both given meanings are direct applications of this idea of vocal or formal commendation.
襃 is the older form of 褒, combining 衣 (clothing) with a phonetic component that also suggests largeness or praise. The modern joyo form 褒 replaced the right side with a simplified structure.
The outer 衣 (clothing) wraps around the inner part like a ceremonial robe. Picture someone being praised and extolled while wearing an elaborate garment, the praise literally enveloping them.
For ホウ, imagine a crowd shouting 'Ho!' in praise as the honored person walks by in their robe: Ho! -> ホウ, and the sound of acclaim fills the air.