It is not. There are some unpatched UAC bypasses on Admin account (UAC set to "Always notify") that are blocked on SUA. The difference is not especially important when using default-deny security in the home environment on well-updated Windows 10 with well-updated software. Anyway, if one has no problems with SUA then it is always better to use it over the Admin account. Generally, SUA is useful as general anti-exploit prevention for Windows & Microsoft software vulnerabilities.