Simplifying inventory accounting for LLC/S-Corp based on new TCJA inventory write off rules

I read that under the Tax Cuts and Jobs Act (TCJA), a retail owner can write off inventory for the year it is purchased, as long as the item is under $2,500 and their average annual gross receipts for the past three years are under $25 million. For 2020 I would like to convert to cash-based accounting and write off inventory cost as an expense. Is this advisable?