The two visa types have different focal documents.
For Skilled Worker, the sponsoring employer's certificate of sponsorship references a specific role at a specific skill level. Where that role requires a qualification (a degree in a relevant field for many healthcare roles, a recognised teaching qualification for state-school positions), the qualification has to be evidenced. The degree certificate establishes that the qualification exists; the transcript establishes what was studied, at what depth, with what grading. UK ENIC assessment, when required, leans on the transcript more than the certificate.
For Student, the focal document is whatever the prospective UK university's CAS letter names. This is usually the immediately preceding qualifying document: an undergraduate degree for a master's applicant, a school-leaving certificate (or equivalent: Indian Class 12, Pakistani HSSC, Nigerian WASSCE, Filipino senior high school) for an undergraduate applicant.
The rule is the same for both: any document in a non-English language needs certified translation. Most major South Asian, African, Filipino and Hong Kong qualifications are issued in English and need no translation. Most Chinese, Russian, Eastern European, Latin American and Middle Eastern qualifications are in the local language and do.