While doing Varshitap, one primarily obtains spiritual purification through tapasya.

Mainly, a person gains:

• Karma nirjara — shedding of bound karmas
• Punya — auspicious merit
• Atma-shuddhi — purification of the soul
• Self-control and detachment
• Increase in samyak bhava — right भावना and inner faith
• Strength of endurance and patience
• Reduction of desires and attachment

In Jain Dharma, Varshitap is not done for worldly gain, but for moksha-marg — progress toward liberation.

So, the real gain of Varshitap is inner purity, karma reduction, and advancement on the path of moksha.