Why trezor/ledger hw wallets are using adalite.io?

Hello,
as you can see from the following page of the trezor and ledger hw wallet manufacturers, they are redirecting to adalite cardano proxy as GUI.

and first generation trezor cannot use cardano.
Is there any spesific reason for using 3th party provider ?

Likely because they’re the one who have primarily developed/worked on the apps.