I don't know if other players notice it, but I don't count on other players noticing anything :P
I pay attention to the needs of my team and throw down the appropriate beat. If my team is pushing a tower, I use Q to buff their auto-attacks. If I see an enemy attack mounting, I throw out my shield to defend or deter the enemy assault. If a quick retreat or chase is happening, I get Celerity going asap.
When it comes to power chords, those are also very situational. Q-chord to burst a squishy, or chunk a tank that is attacking or in need of harass. W-chord to reduce the damage of a sudden aggressor. and E-chord to make sure that slippery assassin, or Singed, can't get away from my team(mate).
I don't know that your team needs to notice the micro buffs. You choose to play Sona because you want to drive your team to victory by being their babysitter. You make sure their clothes are clean, their food is hot, and you tell off the bullies. If they scuff their knee, you bust out the NeoSporin.
It's a role I really enjoy, whether my team notices the buffs or not. I can see the difference I'm making.