Well it depends on your priorities and how smart you are with your miles.
Let's say you have 25,000 miles to use on a ticket. And you earned that based on spending $25k on your credit card. That 25k miles is what most airlines charge for a free domestic round trip ticket. So, if you apply that to a ticket that you could have paid for with $250 cash, that equates to the industry standard of 1%, which is decent, but obviously not as good as 2-3%.
If you apply it to a $500 domestic round trip ticket, that becomes 2% ROI for you and is much better value. $750 domestic ticket can be cashed in for the same 25kmiles meaning 3% return and on up the list. To me, you want to get at least 1.5% return in ticket value for miles used.
Let's now say you have spent $90k on your credit cards over 2 years and so you now have 90,000 miles. You want to go, conveniently, to Bangkok. And you think you're a pimp so you want to know how much it costs in business class. Well it costs 60k miles to go in economy and 90k miles to go in business. As it happens, you could pay cash for that business class seat with about $6k US dollars round-trip. Since you spent $90k to get enough miles to fly in that business class seat for free, your free ticket in lieu of $6k cash represents
6.67% return on your money spent ..... much better than 2-3% wouldn't you say?
So you also see the importance of 2 miles per dollar spent vs the above scenarios with earning one mile per dollar spent. Everything would then be even twice the return of the above.
Follow?
That's why I recommended the card that pays 2 miles to the poster who wants to do a lot of spend on one card with no limits.