To earn a 25,000 one night stay reward, you need to exchange 25,000 Marriott Rewards points. These are debited from your account.
The points you have given come from your spending, in this case, spending as much as $2,500 at a Marriott (assuming you have no bonus for Elite membership), or less if you do.
If you have the Rewards affinity credit card from Visa, spending on Marriott will deliver 5 points per dollar, most other places less, as low as one point.
Thus, if you purchases are in non-Marriott areas and you stays are not bonus enabled (becuase you are new to the program) a "free" night (valued at perhaps $265 with taxes) can cost as much as $2500 dollars! Given all the above footnotes, you might need to spend the equivalent of 1200-1500 dollars.
Elite membership is always a factor for redemption: why accumulate points if you're not going to see benefits from them? If the awards program rewards loyalty by adding bonuses accept them, stay with the program.
An argument can be made that these points, like other benefits, are only valuable when they are used. It may be that the perceived value of points is deflated by the changes in the program itself, as demonstrated last Fall when the program changed to add category 8 hotels.
A counter argument can be made that keeping points has value, but it is a weak one. Points need to be used, and give you something for (almost) nothing.
So, using points, whatever their cost, seems to be a prudent way to be a member of the program. That program will continue to change, perhaps with higher requirements for points redemption per night, so now is a good time to make them as valuable as they are ever going to be.