I've seen this type of comment a couple of times, and and honetly, it doesn't make sense to me: why does the federal government's SL relief create more of an incentive to prioritize paying down the loan now? Say you have a $300/mo payment, and $270 of that is principle and $30 is interest.* Yes, if you make a payment now, you are paying $30 more to principle now than you normally would be, which will then save you interest on that extra $30 for the life of the loan (once interest is charged again). OTOH, if you put that loan payment into the market, you are investing $300 more than you normally would be. So you are able to deploy 10x the amount of "extra" money by putting it into the market -- and the market is very likely to be what will provide the greatest return over the long term.
As another illustration, say the market returns a steady 10% this year, and you have 6 months of relief from your SL payments.** If you take that 6 months to invest in the market, your investment will grow by about 5%.*** But your SL obligation would not grow at all, because everything was suspended. So on the 180th day, you could sell out of the market, send all of the original payment to your SLs, get the exact same principle reduction on your loans, and still have that 5% in profits in your pocket. Using my numbers above, that's @$1800 in payments saved up + $90 in earnings. Now multiply that by 30-40 years in the market, and that extra 5% you started with ends up being a significant amount of money.
Honestly, if you want to focus on prepaying the loans, put the money in some interest-bearing savings account until the relief ends, then make a lump some payment right before the interest kicks in again. That way you'll have the cash available if the shit really hits the fan, and if it doesn't, you'll get the same prepayment benefit and have earned a little extra interest on it as well.
*Total WAG, not intended to be real numbers.
**Again, total bullshit made-up numbers for illustration -- the market doesn't actually work like this, and I am not suggesting you should actually do anything like I am about to lay out here.
***Not really, because you'd be putting your money in each month as the market is rising, so you'd buy fewer and fewer shares each month and thus get less than the straight 5% return you'd get if you put all your money in on day 1.