Gift from Kiruto works this way: First computer pick basket and scondly an item from that basket is picked.
This baskes also have different waiting times.
There are the following baskets:
1) 5 min
2) 10 min
3) 20 min
4) 30 min
5) 40 min
6) 50 min
7) 60 min
8) 1:30 hours
9) 2:00 hours
10) 2:30 hours
11) 3:00 hours
12) 3:30 hours
13) 4:00 hours
14) 4:30 hours
15) 5:00 hours

If players donate 490 (1x R-Gacha) points thay get are garantied to draw from 50 min basket but if they are lucky they can draw from a better basket. Like wise if thet donat 1500 points they are garantied 1:30 basket but with lucky they can draw from better basket.
It is pritty rarely players get to draw from a basket better than minimum garantied basket, only 5-10% chance.
So donation more points garanti drawing from better basket

All gift you offers are converted into points.

The gift a player gets back on average is worth less than half the points offered.