Like with any cashback earning debit/credit card, it's important to note that a workaround to points earning is to purchase them, whether out of pocket or with cashback earnings directly.
Points purchases are typically best done during promo periods. Points uses can be maximized in many ways including but notn limited to promo periods (1, 2, 3). Some of the best points purchase options I've seen in recent memory include (point valuations typically at time of deal):
For Airline Miles:
1.08 cents per point for Aeroplan (TPG valuation of 1.5 cents per point)
If you can get outsized value, Alaskan Air (i.e. when sold for 1.85 cents per point) can be a good option (1.8 cents per point based on TPG valuations)
.42 cents per mile for American Airlines (TPG valuation of 1.68 cents per point)
1.1 cents per point for Avianca Lifemiles (TPG valuation of 1.7 cents per point)
1.25 cents per point for Etihad (TPG valuation of 1.4 cents per point)
.73 cents per point Finnair Miles (No TPG valuation - US to Europe, Dubai, or Israel can go for 45k in economy or 80k in business 1 way flying Finnair out of NYC, Miami, Chicago, Dallas, or Los Angeles with no fuel surcharges, so <$350 and <$650. On long-haul there's also 1 free stopover.)
1 cents per point for Frontier (TPG valuation of 1.1 cents per point)
Virgin Atlantic (if your account is based in the UK) for 1.24 cents per point when a 60% discount (TPG valuation 1.5 cents per point)
For Hotel Points:
.49 cents per point for Choice Hotels (TPG valuation of .6 cents per point but I think that's low and that buying Choice points when that low cost is underrated. I've seen these worth >21 cents per point in 1 example [while no longer in their portfolio, 3 bedroom suite stays in Aspen would go for 6k +$180 vs around $1500 if paid in cash per night] while the same valuation of .6 cents per point on TPG & it's extremely easy to get >.6 cents per point in value on these. For one that comes closer to that than others I've seen, check out multi-bedroom suites at Bluegreen Vacations Big Bear Village, Ascend Resort Collection if you can find availability, which can go for over a thousand per night in snow season itself. That said, the booking window is only 100 days out on points and you're restricted to using them for yourself and family on the reservation unless you're present while non-family stays in the same or separate rooms on the same reservation)
.5 cents per point (regularly recurring promo) for Hilton (TPG valuation of .6 cents per point)
1.04 cents per point for Hyatt (TPG valuation of 1.7 cents per point)
.5 cents per point (regularly recurring promo) for IHG (TPG valuation of .5 cents per point)- ideal when combined with the current and legacy annual fee incurring cards for 4th night free on points and stackable 10% rebate on points & used on stays with high-value per point. Using that method I recently got 2/3 off on an 8-night stay I booked.
.781 cents per point for Marriott (TPG valuation of .8 cents per point)
.35 cents per Radisson Reward (TPG valuation of .4 cents per point)
.93 cents per point for Wyndham Rewards (TPG valuation of 1.1 cents per point)
For Car Rentals:
2.79 cents per point on Hertz (no TPG valuation but easy to get value out of, especially if you have Hertz status such as via Delta Gold-Diamond status or perks such as through the Amex Platinum.