I think that's more of a psychological sense of safety... or something. UFO showers you with extend to the point you can reach the cap by Ichirin, then proceeds to strip you from them all the way to Byakuren, where you have a few of them left. Which is propably why one or two lossy deaths on stage 5 don't hurt as much, especially since you get 2 bombs per life and can't lose more than two.
Contrast SA, where you get much less extends, shot types and bombs are relatively horrible, bombs are tied to power so you weaken yourself with bombing and you're deprived of extends if you die on spell cards. That, and if you have more than 3 lives and die on the boss, you have only 2 power and thus 2 bad bombs till the next death... unless you make it to the next stage with low power, in which case you get the chance to recover power and squeeze so much more from the current life.
It's just the matter of psychological pressure and the constant awareness than one bad death can start a domino effect of deaths and cost you a run, plus you're encouraged to risk up to 4 and potentially more bombs if you want to do decent damage to bosses. To me, Koishi's patterns felt doable, but the clear seemed completely impossible at first because there was simply no resources to do so. UFO's much more forgiving in that matter, as it feels you have to constantly play well as opposed to avoid fatal mistakes at wrong points (the cruel trick with S4 midboss Nue drop nonwithstanding).