Eh, I'm someone who tries to 1cc on Normal. If I accomplish that, I try again on another character, to get all the endings. That's why I play. I've dabbled in trying to clear Extra or Hard but have never succeeded and don't have much motivation to try. Anyway, I can say I've cleared every Windows game on Normal, with maybe half the shot types. I think I can honestly say I'm not very good.
Maybe it's because I'm not too good though that I find most of my pleasure from the act of trying. Dodging things, capturing spellcards, conserving bombs, whatever, all this stuff is enjoyable, but mostly because I need to get better at them to clear the game. It's a means to an end. And quite frankly I think of it as a resource game, first and foremost. "Never dying" is cool and all, but I have not once made that my goal. My goal is to beat the game, not to dodge everything. And, from experience, learning patterns and memorizing fairy spawn locations is almost completely irrelevant compared to conserving resources. I usually don't bomb as an emergency lifesaver, because honestly I don't trust my reflexes enough for that. I bomb when I think I might be in danger in the future. When I encounter a pattern that I think I won't be able to dodge. I give up before I try and just bomb it. Because that's the safest way to play, for me.
So, all that said, I think the number of lives available is a very important aspect of the gameplay. It tells me what I can expect and what I have to do to win. It's part of the gameplay balance just as much as the patterns themselves. And I loathed TD. Seriously, I hated that game when I played it. The lack of lives and the stupid Trance system that punished you for dying by making it harder to collect lives... I hated it all of it. The life system was so bad that it also made me hate the music and the spellcards, something I usually love and the main reason I play the games. Maybe you can try to convince me that I'm "playing it wrong" but having very few lives and having to do stupid things to collect them made the entire game less fun. Maybe if you're actually an expert or someone playing for score you can just think "how can I dodge everything?" and decide that the number of lives is irrelevant, but aren't you the one who's actually ignoring a huge part of the gameplay? You're supposed to die. You're supposed to bomb. Dodging everything, while maybe the ideal you strive for, is actually playing the game wrong. In a certain sense.
On the other hand, I absolutely loved SA, which everyone else seems to be lumping with TD in "cruel gameplay systems". It's by far my favorite game in the series, and I love the life mechanic. The best part is that it never encourages you to risk your life to get more lives, something that was a huge flaw in both UFO and TD. Safe, cautious, conservative play becomes a self-reinforcing cycle.