Charity isn't an Alternate for Qurbani:
Some people think that instead of offering a Qurbani they should give its amount to some poor people as charity. This attitude is totally wrong. Actually, there are different forms of worship obligatory on Muslims. Each one of them has its own importance and none of them can stand for the other. It is not permissible for a Muslim to perform salah instead of fasting in Ramadan, nor is it permissible for him to give some charity instead of observing the obligatory Salah. Similarly, Qurbani is an independent form of worship and this obligation cannot be discharged by spending money in charity.
However, if somebody, out of his ignorance or negligence, could not offer Qurbani on the three prescribed days (10th, 1lth and 12th Zulhijjah) then, in that case only, he can give the price of a Qurbani as sadaqah to those entitled to receive Zakah. But during the days of Qurbani no Sadaqah can discharge the obligation.
Question: During the days of Eidul-Adha is it better to offer Udhiyah/Qurbani (sacrifice) or give Charity (in general)?
Scholars of Islam have stated that its better to offer Udhiyah/Qurbani (sacrifice). Ibn al-Qayyim (RA) said in Tuhfat al-Mawdood:
الذبح في موضعه أفضل من الصدقة بثمنه ولو زاد ، كالهدايا والأضاحي ، فإن نفس الذبح وإراقة الدم مقصود ، فإنه عبادة مقرونة بالصلاة
The true philosophy of Qurbani:
The present-day Qurbani is offered in memory of the great model of submission set before us by the great father Ibrahim عليه سلم and the great son Ismael عليه سلم . So Qurbani must be offered in our time emulating the same ideal and attitude of submission.
This, then, is the true philosophy of Qurbani. With this in mind, one can easily unveil the fallacy of those who raise objections against Qurbani on the basis of economic calculations and depict it to be a wastage of money, resources and livestock. Unable to see beyond mundane benefits, they cannot understand the spirit Islam wants to plant and nourish among its followers, the spirit of total submission to Allah's will which equips man with most superior qualities so necessary to keep humanity in a state of lasting peace and welfare.
Qurbani is nothing but a powerful symbol of the required human conduct vis-a-vis the divine commands, however "irrational" or "uneconomic" they may seem to be in their appearance. Thus, the distrustful quest for mundane economic benefits behind Qurbani is, in fact, the negation of its real philosophy and the very spirit underlying it.