That's so hypocritical.
If we're debating choosing a dub for the sake of immersion, having all the added voice acted bits definitely add to the experience. When a lot of them are not getting subtitles, it becomes extremely annoying if you don't get what's being said. In no way do they "matter" for the big picture or anything like that. But they greatly contribute to the game feeling lively IMO.
I'm all for people being aware that battle dialogue isn't subtitled, but let's also not pretend the player is missing anything without it. The bulk of it is simple one word phrases that most people who've seen a subtitled anime in their life would understand even without subtitles - any time a boss has a line to say, or the cast have something to respond with, it's subtitled. Any time the navigator warns you an enemy is charging, it's subtitled. Any time you hold up an enemy to negotiate, it's subtitled.
I wouldn't say these lines contribute to the game feeling lively in the slightest, and by the 20 hour mark you've heard every battle line a dozen times over anyway. The dialogue that does add liveliness is the chatter around the city that changes day by day, or the conversations your party members have as you crawl through Mementos, or just the main story and confidants - and every single one of above is fully subtitled.
I get that you like the dub, and that's great - but let's not misinform people and imply even a remotely substantial portion of the game is unvoiced to try and sway them towards the dub, when that's hardly true.