Isn't it all in the timing?
Personally I see no need for this, whilst the time seems extreme like people have said supercell need to make their money. I rarely use spells for raids due to both time and elixir cost so I only train them for war - usually the first one I train during prep day because I know the tactic I am likely to use and the spells required for it. Then the second set of spells I train straight after my first attack - I rarely even need to boost my spell factory nor my barracks for this because I work full time so I either attack in the morning or the evening or the lunch hour depending on the timing.
