Is SAD worth it? Tell me your parameters. It is completely different environment in a level 20 white room vs. playing levels 1-20 and spending time at each level. Which is different than starting at 5th, which is different than starting at 10th.
How the character plays through your first 2-3 ASIs will tell you if spending a level for SAD - but also delaying other things by getting that level is great, unacceptable, or just another path. And since that's likely close to half your time playing the character IF you start at 1st, that's really where you want to focus you effort in order to have an answer to the question.
Unless, as I said, your parameters are different. Starting at a different level. Rolled ability scores. Who knows. But a level 1-20 game that's what you should look at; looking at it only for the last 5% of play is worse then useless, it's actively misleading.