Bitcoin is money. Why would you want to mix database and money? Do you want to add random pictures to your PayPal transactions?
I totally get why they don't want tons of data going on to the BTC blockchain and inflating transaction fees, possibly causing the price to tank as it did in the 2018 crash. I strongly believe that this crash was mainly due to the fees, as it coincided perfectly with the upper TPS limit.
Wrong. Bitcoin crashed because it was a speculative bubble. The $20,000 price mark existed for some minutes, and above $13k existed for only days. There's nothing strange with it crashing the way it did. The fees started getting high long before the price reached it's peak, so fees were definitely not the factor. No one was thinking "wait a second, with such high fees Bitcoin is not suitable to be a currency, sell, sell, sell", it was all pure speculation - buy low, sell high, get out.