No one knows.
“Spontaneous” spellcasting is never defined in the rules. In fact, the only class features in the game to actually refer to themselves as “spontaneous” spells are the cure and inflict of clerics, the summon nature’s ally of druids, and similar—cases where normally-prepared spellcasters get a little bit of spontaneity. The word “spontaneous” does not appear in the spells class feature of bards, sorcerers, and so on.
Instead of being defined, the concept of spontaneous spellcasting was left as “I know it when I see it,” which is probably fair in 99% of cases but corner cases like Alacritous Cogitation and even the actual spontaneous spells features of clerics and druids leave people scratching their heads.
In short, ask your DM. In most cases, burning a feat is probably fair cost to count, but I could see situations where that wouldn’t fly with me, because I want whatever to be special for spontaneous casters—and Practical Metamagic might be one of them, for me.