It has some problems, for instance it seems to make no distinction between various levels of control a given empire could have over its territory, simply coloring everything in a solid shade (Ottomans controlling Egypt in 1880 is just... wrong). It also makes a lot of small mistakes, and occasional big ones (what stands out to me is that the Ottomans magically go from controlling nothing in Hungary in 1526 to controlling 2/3rds of it the following year, then magically lose it all again in 1692). But it might be useful to get a general sense of what empires were where during a given era. Just don't look at the minute border changes too closely, they're full of errors.