Short answer - yes, blank keycaps [strike]really[/strike] help.
The number row and some pinky characters have been my touch typing weakness, for a long time. When I first learned to type, the class didn't get through it. Additionally, I've a long standing bad habit of going to the ten key first. I still use the numberpad (blank, since the whole board is blank), when I'm impatient, which probably sets me back some.
I think if I actually spent some time with typing exercises and games, in addition to my blank keyboard that it would help faster. The simple fact is, a lack of use causes the learning to go slower. I'm sure it doesn't help that I revert to ten key, when I'm impatient, lol. Some how I think my visual memory is hurting me. Even if you're not looking, if you can think of where the key is, by bringing up a mental visual image, you'll still be slower.
I don't have your decimal problem at all, though. That's because I learned the period along with the letters. Additionally, the numbers are a larger reach than the decimal. For me, the more on home row the keys are, the more ingrained in my memory they seem to be.
My sister doesn't touch type and is horrified

by my blank keyboard. That said, she found my gaming sensitive mouse more daunting, than my keyboard, when she actually had to tackle it. She did crutch on notepad some, though. I offered to turn down the sensitivity on the mouse, but she didn't let me.
Well, one hand typing does go slower for the keys not normally done with that hand on the blank keyboard. All the more reason to get away from your desk, when eating!