This is only true if you consider less play-time per campaign to be something negative.
There are plenty of historical conflicts during EU4's time frame that would make excellent mini-campaigns: the Thirty Years' War, the English Civil War, the War of Spanish Succession, the Seven Years' War, the American Revolution, the Napoleonic Wars, and a bunch others. There are also a bunch of interesting countries such as the Mughal Empire, the Maratha Confederacy, the Qing Empire, and the United States that would be interesting to play as in their historical contexts.
You technically lose historical decisions and some flavor events, but so what?
It's also worth mentioning that the later start dates offer an alternative to having to build your empire from scratch. Choosing Austria, France, Otto, Portugal, or Spain in 1492 or 1517 instead of 1444 lets you start with these respective states already established as great powers instead of having to crawl your way up.
There's certainly value in alternate EU4 start dates, both flavor-wise and gameplay-wise.