It does mean cash. Its more efficient to let individuals turn cash into quality of life, than just providing services.

One of the main bits with UBI is that government is very slow to adapt to changing requirements. By mandating what people get, it leads to a lot of inefficiency. A more extreme example is the planned economy of the USSR. It just didn't work well.

UBI lets the people involved decide what is more effective for them. E.g. 1 person might decide that turning the heating up is good. Another might invest in merino wool underlayers, since they tend to work outside.

An understated point though is that the basics should be easily attainable. Then again, that's a basic measure of a society, even if multiple countries, that should be able to do better, are failing at it.