I don’t think I know of any other Indian festival where you buy something actually for others. India has so many festivals throughout the year that it makes every seasons enjoyable. (We have festivals in every season and if there isn’t one then birthdays and anniversaries make it up). So on every occasion we purchase something or the other and that too only for our own use. New clothes, sweets, home furnishings, home decor almost everything you can think of anything that is usually purchased during the festivals is entirely for personal use. In other words, you can celebrate the festival without a community too. Of course if you have a community then it is fun however, in the absence of it also you can celebrate it in your own way.
For example, on Diwali you can decorate your house with oil lamps, candles and electric lights, Christmas too you can decorate the Christmas tree in your house and but presents for your family. Or even during Durga Puja you purchase new clothes and visit the pandals with your family. In general talk about any festival you can celebrate with your family members only.
Whereas on HOLI you buy colors, pichkari, thandai and all the other accessories for other’s use. You cannot celebrate it alone with your family members. You need a community to celebrate this festival and that too spend your money to buy things for others. So in actual terms, HOLI is the ultimate community festival and that is the only reason I love it more.