I'd agree with you on this, a shavette certainly teaches you a tender, careful touch. I found they are very unforgiving, and will bite you in a flash, and as you point out, if you can use one of these, then the change to straights is much easier than say going from a safety razor to a straight, at least that was my experience.
+1 to this and Ace's comment. I started with a shavette and was able to master it rather quickly getting irritation free BBS shaves and when I switched over to a straight I found it a very easy switch (after I got my straight very sharp).