New Testament believers like to erase the "OT" feasts and say that they are done away with (they replace them with pagan feasts/holidays such as Ishtar/Easter, Halloween, Valentines Day, Xmas, etc...)
However, the book of Zechariah clearly states that in the future kingdom, there will be NO RAIN upon the land of any nation who does not come up to Jerusalem for the feast of Tabernacles. That nation will be judged with plagues.
Well, if scripture says that these are 'perpetual statutes t/o all our generations' to be observed 'forever'....(see Exodus, Leviticus and Deuteronomy for instructions on these feasts), then I think we should take note and do them!
Perhaps there is some BENEFIT that the Creator had in mind for commanding us to do so!