Loading SPM from AWR

Hello All

We have a couple of questions on the loading of SPM baselines 

Starting with 12.2, now we can load the baselines from AWR snapshots and it seems that prior to that we had to create a STS from AWR snapshots and then load the baselines from STS but effective 12.2 we dont have a create a STS

Is that true?

If yes, what is more efficient / recommended by oracle? Create an STS from AWR and then load that into baseline OR load from AWR snapshots directly?

Also, lets suppose that we have data that we need for loading the SPM baselines stored in AWR snapshots 3 days apart