Even if you want to consider that them paying you to watch adds, which is frankly ridiculous, that's a terrible value on one's time. The average Netflix viewer watches it for 2 hours per day or 60 hours per month. Assuming Netflix would only show 5 minutes in commercials per hour that is 5 hours in commercials per month or a pay rate of $1/hour. Hard pass.
This would fit my use case as well for SS. A year of Hulu w/ads via their Thanksgiving special for $2 a month... I was psyched at first, but as time went on, I was using it less and less. Hulu's ads are roughly 10 minutes per hour of content, and it really does destroy your ability to watch stuff on a regular basis, let alone binge stuff.
Plus, you had to rewatch ads that you already saw, within the same session! 
Towards the end, I actually dreaded using it! I did find one show that had 1-hour episodes, but only had one ad at the beginning, so that was pretty neat!

When it came time to decide to do that promo again (at only $1 per month), it was a hard "na-ope!" from me. Hulu IS very nice, but when I resub to it, it'll be ad-free or bust.
If I were to play devil's advocate, there are definitely use cases where with-ads is desired...
1) people just need to save $$
Such as college students, or those raising families. I rotate SS so I don't pay that much per month, but I know some families where it's too hard to coordinate this (e.g. this is going to be Netflix season, then we'll switch to Disney+ for the next 3 months after that, etc.), so having multiple SS makes more sense for them. Having the cheaper, w/ads plan, the savings add up.
2) They don't use it that much
Some people are very casual with SS. They'll watch only a few hours per month, to a few hours per week. They won't get as much value from the ad/free plans. With such infrequent viewing, it's easier to put up with less ads. Hulu for $1 or $2 per month is an excellent value for them.
3) Use commercial breaks to do other things
Some get up and do some aerobics, move around. Do some chores around the house, get some water, take a piss break. Me, I much prefer to just "make my own commercial breaks" by pausing, but to each their own.