“At first glance, today’s decisions looked, walked and quacked like tapering,” Carsten Brzeski, chief German economist at ING-DiBa in Frankfurt, said in a note to clients. “Draghi gave his best to convince everyone that it is not tapering. We tend to believe him.”

Below are other issues that have raised concerns among some economists, investors and central bankers.

The Rise of Inflation

“Uncertainty prevails everywhere.” — Mario Draghi, warning that despite inflation rising, the eurozone economy is still fragile.

The reasoning behind the European Central Bank’s asset purchases is that they are one of the most effective ways to bring inflation in the eurozone closer to the official target of just under 2 percent. (In November, the annual inflation rate was 0.6 percent, a level considered unhealthy for the economy.)

Mr. Draghi said on Thursday that inflation would rise next year along with the price of oil. That is allowing the central bank to reduce the size of its asset purchases, which are a form of money printing.

But he also suggested the eurozone economy still was a long way from being in good health.

Signs of higher inflation have already prompted some economists to press for cuts to the bond buying, which critics say has distorted prices. When the European Central Bank ends the so-called quantitative easing program, they say, the shock to bond prices could destabilize the fragile eurozone economy.

The central bank’s “argument in favor of bond purchases no longer holds for 2017,” Clemens Fuest, president of the Ifo Institute, an economic research group in Munich, said in a statement. “The negative side effects of the E.C.B.’s bond purchases will come to the fore.”

Pushback Against Overhauls

“Our view is that easing monetary conditions should help undertaking structural reform.” — Mr. Draghi, arguing that central bank policies have given political leaders more space to push through changes.

As he has for years, Mr. Draghi beseeched leaders of eurozone countries to take steps to help their economies grow faster, warning that the European Central Bank cannot guarantee the health of the common currency area on its own.