Distiller's Malt exists primarily to feed a still, not a fermenter for beer — Scotch and grain-whisky production wants maximum fermentable extract from the smallest amount of grain, which means maltsters supplying that market select and process barley for very high diastatic power and low protein/nitrogen content, since excess protein reduces spirit yield and can cause haze problems downstream in distilling. At roughly 150 °Lintner, it carries even more enzyme headroom than Pale 6-Row, the highest-diastatic malt most homebrewers reach for.
Brewers occasionally use Distiller's Malt specifically for that enzyme surplus — a mash carrying an unusually heavy adjunct load, or one built around several low-diastatic specialty malts at once, can lean on Distiller's Malt the way a high-adjunct American lager recipe leans on 6-Row. Its low protein content also means less contribution to head retention and body than a standard base malt provides, a trade-off worth accounting for in a recipe built around it rather than treating it as a drop-in Pale 2-Row substitute. It's a specialty sourcing item at most homebrew shops rather than a shelf staple, since its real market is commercial distilling rather than homebrewing. A brewer who does track it down should check the diastatic power on the actual spec sheet before relying on it for an unusually adjunct-heavy grist, since the exact figure varies by maltster and barley lot.