  The phenomenon of field-induced superconductor-to-insulator transitions
observed experimentally in electron-doped SrTiO$_{3}$/LaAlO$_{3}$ interfaces,
analyzed recently by means of 2D superconducting fluctuations theory (Phys.
Rev. B \textbf{104}, 054503 (2021)), is revisited with new insights associating
it with the appearance at low temperatures of field-induced boson insulating
states. Within the framework of the time-dependent Ginzburg-Landau functional
approach, we pinpoint the origin of these states in field-induced extreme
softening of fluctuation modes over a large region in momentum space, upon
diminishing temperature, which drives Cooper-pair fluctuations to condense into
mesoscopic puddles in real space. Dynamical quantum tunneling of Cooper-pair
fluctuations out of these puddles, introduced within a phenomenological
approach, which break into mobile single-electron states, contains the
high-field resistance onset predicted by the exclusive boson theory.
