Borit karshina lAma he baa or lEma

Question

A simple question on Nussach Hatefila. On the basis of Tosfot Yom tov

מסכת ערלה פרק ב - משנה ו
וּלְמָה אָמְרוּ כָּל הַמְחַמֵּץ וְהַמְתַבֵּל וְהַמְדַמֵּעַ לְהַחֲמִיר‏

See Tosfot Yom Tov "והלמד שימושית והקריאה בשוא והמ"ם פתוחה...‏" Pitum Haketoret

בֹּרִית כַּרְשִׁינָה לָמָה הִיא בָאָה, כְּדֵי לְיַפּוֹת בָּהּ אֶת הַצִּפֹּרֶן, כְּדֵי שֶׁתְּהֵא נָאָה. יֵין קַפְרִיסִין לָמָה הוּא בָא כְּדֵי לִשְׁרוֹת בּוֹ אֶת הַצִּפֹּרֶן כְּדֵי שֶׁתְּהֵא עַזָּה, ‏

Why Lama (why) and not Lema (what is the purpose)?
The same problematic exist with bema, bama/bame or kama kema
במרה כמה למה
Open question or multiple choice question. I think that the point is this. Borit karshina --> multiple choice question for which spice, which function --> Tsiporen... naa
Yayn Kafrisin --> m.c.q -->tsiporen ...aza

Answer 1

In Pitum HaKetoret, the "למה" is the "regular" "למה", meaning "why". However, according to R' Ovadia from Bartenura, the "ולמה" in Orla means "ובמה", i.e. "in which case" (and not "and why"). Therefore, to explain how R' Ovadia's reading sits well with the text, the Tosfot Yom Tov explains that the "ולמה" isn't the "regular" "למה" (with a kamatz under the lamed), it's a "lamed shimushit", i.e. "ל-מה", meaning "for what purpose", or in our case, "in which case".

To clarify - both your suggestions would fit the text in Pitum HaKetoret (just like asking "why" vs "for what purpose"), but as mentioned above, that's not the distinction made by the Tosfot Yom Tov in Orla.