Effectively - with no conversion bonus - the Tesco card gives 0.6 Avios per £1. This is not great.
The Santander card I don't know (no longer available I think) but an Amazon MasterCard gives 1 per cent in Amazon vouchers which are as good as cash to most people.
You would need to value Avios at well over 1.6p before the Tesco card was better than the Amazon one in pure cash terms. And few people do. However, if you gamble on another Tesco to Avios conversion bonus at some point then the numbers change.
And welcome to FT!