Mh, not necessarily, part of the problem arises from mobiles that don't do 5.8ghz wifi, so their only way to connect to the remote then is 2.4, which kinda kicks the drone on 5.8; that's not that bad either, if it wasn't for:
ce rules about the energy output on those bands, compared to fcc ce allows a lot less, and even less for 5.8 than for 2.4. And to make it worse, in Europe there is radar operating on those frequencies, so ce compliant devices have to implement dynamic frequency selection, which means they have to stop, check for radar and if they detect it basically clear the frequency for it. Go figure. Now the real fun part is that the spark allows dfs to push the channel to channels that are actually not meant for use in Europe, so it will find an happy empty channel there.. So even if your phone supports the band, you might end up still losing the connection as most phones don't go to channels they are not supposed to..
Now all of those circumstances are rather hard to test, especially if you are not aware of them, or don't have them in your country.