Sunak was hinting at the same last week.
They are simply looking for change behind the sofa - if you catch a train to work you (often); buy a ticket, buy a coffee, buy some lunch, buy a pint after work, buy a ticket back. All taxable goods.
Another thing is office building standing empty, no cleaners, receptionists, security. They won't have a job, an neither will the architect of the next London office skyscraper, or the construction worker who was going to build it.
People working from home is not good for Boris' tax pocket.