Of course the railway dumps you on the edge of central London leaving you to take the tube or Elizabeth line to finish your journey in while the coach drops you at Marble Arch or Victoria.
Certainly an advantage for tourists, though Paddington+Liz is probably more use if going to the City. I'd suspect that is the rough split.
GWR do also seem to be attempting to price-and-confuse off tourists, with Off Peak restrictions applying on the outward out of London in the evening peak to Oxford which is unusual for journeys of that length in the South East*, though curiously £9 Advances seem to be available on a lot of trains in very high numbers so they could charge more reasonably if they wanted.
(I've often moaned about Paddington being in the sticks, and indeed it is, but the Lizzie makes that far less of an issue, as does the addition of e-bikes to the "Sadiq cycle" fleet!
)
* Some ex-NSE TOCs have asymmetric restrictions where there are evening restrictions on the return half of a return to London, but not on the outward half of a return from it, some others have an intermediate off-peak step that's valid in the evening but not the morning e.g. LNR, but few seem to be Anytime only if you want to leave London for a relatively local destination like Oxford from about 1600-1900.