Choosing to remain in the Astral Plane indefinitely always results in death, no matter how you go about doing it.
As others have stated, however, your skill ramps in your next life are a function of how long you live and how hard you train in your previous life.
So while you might restart earlier, you'll ultimately have a lower maximum skill cap than you otherwise would. As well, to reach master/grandmaster in an earlier life, requires the boon you obtain from teaching as an older character.
In the absence of that, it'll take more lives to attain that level of mastery.
Can you suicide to start over sooner? Yes. Does it really provide any benefit from a statistical point of view? No. Not really.
Does it allow you to spend more time as a "younger" character? Yes. Does it cost extra money year over year to achieve? Yes.