Which also keeps surprising me is that the activity here is always in relation with the value of steem. While, like you wrote, there is not difference if you are just trying to power up!
At least in my understanding, it is only a perception.
When the upvotes have much value it is more expensive to but steem, while if the upvotes has less value the streem price will also be cheaper.
There is a difference however with the SBD ratio to steem. The higher the steem price, the more chance there is that the SBD will be left alone, meaning less Steem for an SBD.
When the steem value is low on the other hand, the SBD could even have more value than Steem and we have hit the jackpot!
Or I see this wrongly!

Cheers,
Peter