On average, more or less. See this post (tldr: average 2.3c on latest trip):
https://www.gocurrycracker.com/another-round-the-world-trip-another-7000-in-free-travel/But, points have less flexibility than cash. So if you are only earning 1 pt / $1 and only getting 2.3cents/point, then 2.5% cash back is better and easier. (Most of our spending is on travel & dining out, earning 3pts/$1, so we actually got more like 7%+ back.)
When looking at just 2.5% cash back versus the alternatives, best would be put all spending on new cards for signup bonuses.
Spending $45k on the Alliant card is worth about $1100 ($1,125 - $59 annual fee.) Not bad, but not much travel either.
A 50k signup bonus on the Sapphire Preferred by itself is potentially worth $1150 (assuming 2.3c/pt)
After minimum spend on that card you still have $41k budget for the year. Maybe you apply for another card or 2 with $6k total min spend, earning another $500 - $1000 in signup bonus value.
Total remaining budget: $35k. That can be targeted towards high value category cards (e.g. 3pts/$1 on travel, 5 pts on groceries / gasoline, etc...) Maybe this is $10k total.
Now you have $25k budget remaining for the year. That can go on a cash back card, but:
$25k on Alliant = $625 - $59 fee = $566
$25k on Citi Double Cash = $600 (better)(no annual fee)
$25k on Freedom Unlimited = 1.5 pts / $1 = 37,500 points. Cash value is $375. Booking travel with Sapphire Reserve value is $563. Or if you transfer and get 2.3 - 2.5c/pt, then $863 - $938.
Subtract fees in year 2 for Preferred or Reserve (if applicable, minus $89 - $150.)
So it depends. Straight cash back is simpler / easier, but not the highest ROI. We definitely do better with the points.