Formal practice includes reflections. To sit down and actually reflect, that's part of the formal practice. So maybe, is this person thinking that can they skip doing any formal practice and just every once in a while during the day reflect? You can do it that way, but your practice is not going to be very strong or develop very deeply unless you practice the reflections in a quiet environment.
Just think of it for a minute, piano, whether you have played it or not, I'm sure you can identify with it. Say I want to learn piano. On my first day I have them put the piano on the corner of a street in Bangkok so I can practice there, with all the noise of the trucks, with all the music of the shops and every thing else that's going on my first day at playing piano. I'm going to practice on the streets of Bangkok. What do you think, good or bad? Stupid! Nobody does that, nobody learns the piano playing on the streets of Bangkok. They go to a quiet room, they have a teacher explain a few things, then they practice in the quiet, in the quiet. They need a certain environment to practice the piano. Now when they are very good, and if they're so good that they play for performances whatever, or if their so good they could set up on the streets of Bangkok, then they could play and they wouldn't be bothered by all the noises, whatever. Maybe if they're that good they wouldn't be bothered, but if they want to learn a new song, would they stay on the streets of Bangkok or would they go back the quiet room?
Same thing in meditation practice, if you want to make your practice strong you're going to need that quiet time, you're going to need some formal practice. We also want to do it in our daily life. We want to reflect as often as we can, but you're not going to be able to do it very well unless you've practiced it a lot in the quiet then it will come up easier, when it's noisy.