Yes. Alpha-arbutin is gentle enough for daily use, and daily use is how it works.
That is the whole answer. The detail is below.
Why it is gentler than the alternatives
Alpha-arbutin interrupts the enzyme that produces pigment. It does this without the irritation of harsher brightening agents, and without the sensitivity that acids bring.
Irritation is not a side issue here. Inflammation causes pigment, so an aggressive brightener can leave you worse off than you started.
Morning, night, or both
Both is fine. If you use it once, use it at night.
There is no photosensitivity concern the way there is with acids or retinoids. Sunscreen is still non-negotiable, because ultraviolet undoes the work directly.
What it works well with
Niacinamide. They approach pigment differently and are frequently formulated together.
Vitamin C. Fine, though some people find the pair a little much daily. Alternate if your skin tells you to.
Hyaluronic acid and ordinary moisturisers. No conflict at all.
What to be careful with
Strong acids or a retinoid on the same night can irritate. Irritation causes pigment. Alternate nights rather than layering.
How long before anything happens
Six to twelve weeks for newer marks. Longer for older ones.
Alpha-arbutin is slow and steady rather than dramatic. That is the trade for not irritating your skin, and on pigmentation it is usually the right trade.
If you are pregnant or breastfeeding
Ask your doctor or pharmacist before starting any new active. This is a general precaution and not a warning specific to alpha-arbutin.