yup! very true.
I love grooved bearings for screwing around but when I want to seriously throw I use a yoyo with a ct or flat bearing.
When learning suicides you really do want some minimal and very light contact between the yoyo wall and the string to help keep the loop open. Grooved and KK bearings make this a tad harder since the string is centered while on a CT or flat the string has a greater chance of being kept open by the wall. If this weren’t true, then many of the newer yoyo’s wouldn’t be designed with this in mind. Just think Drop Bear, Arctic Circle, Gelada…all designed with a wall that helps with these types of tricks.
And like many have stated a good string that is a bit stiffer and with neutral tension (the string doesn’t wind up but instead stays nice and loose) is going to help you out a lot.
But…with practice you can suicide with any bearing. If you’re still learning though, try for a CT or flat bearing to help out with your suicides and try for some strings like Twisted A1 like Sniffy suggested or Toxic BG or Dragon Strings which I have also found to work as well as the A1. I’m playing my Omnicron with Twisted A1 on a CT bearing and suicides are a piece of cake!