Rossini and the Lyric Tenor

Matthew Polenzani - Rossini: Rigoletto - Parmi veder le lagrime
http://www.youtube.com/watch?v=j7xrPHPFH9Y

Stanford Olsen - Rossini: Tancrendi - O Dio! Ah Segnar invano io tento
http://www.youtube.com/watch?v=N4B2vCxmtFo

So, I guess it's 'Rossini Lyric-Tenor Day'. This week's listening selection was purely coincidental.  It is evident that both tenors are very skillful singers who seem to effortlessly navigate their vocal ranges--particularly the high register.  Tenors of this type mystify me. It's hard for me to image singing so high in the register with such a delicate, light and clear tone. Furthermore, their upper registers are so consistently dove-tailed into their lower register that it is often hard to tell where the 'switch' occurs.  Both sing with an almost seamless legato but still their tone is 'punchy' and 'reedy' when musically appropriate. Are these two tenors examples of Bel-Canto singing? What exactly does that mean in the context of current performance practice, orchestras, performance halls, etc? Is this a technique still taught and applicable to all voices types--dramatic or otherwise?