Answer: When the Bnei Yisrael sang shira after crossing the yam suf, they said 'zeh eli veanvehu, this is my G-d and I will glorify Him'. The Gemara (Sukka 11b; Nazir 2b) writes that this passuk teaches us that we shouldn't just perform mitzvos in their most basic manner, but we should make extra effort to build a nicer Sukka and spend more money on our lulav and esrog, etc. Similarly, the Gemara (Shabbos 23b) teaches that one who is particular about lighting their Shabbos candles will merit having children who will be Torah scholars. The Tur (OC 263) and Bach (OC 263:1) qualify this to those who make beautiful lights. Rashi writes that this applies equally to the Chanuka menora.
Thus, the Shulchan Aruch (OC 673:3) writes that earthenware dishes should not be reused as they aren’t nice when used again. The Mishna Berura (673:28) adds that one should go the extra mile to ensure that they have a beautiful menora. Likewise, the Chida (Birkei Yosef OC 673:7) and Kitzur Shulchan Aruch (139:5) write that one who can afford to, should buy themselves a silver menora.
Similarly, the Kaf Hachaim (OC 673:60) writes that according to the Chessed Avraham, there are fiften levels of how nice a menora can be. The very best is a gold menora followed by a silver one and then various other semi-precious and regular metals, followed by glass, wood, bone, and various earthenware ones, etc.
R’ Shmuel Wosner (8:157) points out that even though the actual oil may be placed into a small glass cup, this doesn’t detract from the hiddur mitzva of using a silver menora.
Especially on Chanuka, when we are particular to perform the mitzva of lighting the menora in the very best manner, mehadrin min hamehadrin, it is most appropriate to use a beautiful menora rather than a cheap one.