Really and honestly, unless you are in a specific area for a number of days the answer is generally no. And the domestic entire UK rail pass is now so over priced it really isn't worth it.
As an overseas visitor you are looking more at the Britrail range of rail passes. Many have no domestic UK equivalent, for those which do the Britrail version is much better value.
To take the comment above-
You will most likely receive advice here that advance tickets may be a better value, the fact that you still need to make reservations on long distance trains when using a pass, etc.
Except for the night trains there are no UK services where you need to make a reservation. Some where it is adviseable to, but none where you have to. For those where it is adviseable never make them through ACORP (the Britraiil retailer) as they charge- any reservation is free when made at a UK station.
The first step is to document the individual rail journeys, then price them individually, then compare to the price of the pass. Note that short journeys, such as from Bath to Oxford, aren't worth using a rail > pass day for.
True
A main benefit of the pass is the flexibility to avoid a schedule set weeks in advance, although maybe now not quite as simple as "jump on any train."
Not so- very good advance fares are now available on many routes until days or even as little as 5 minutes (on some routes) before travel. This is said repeatedly on this forum, and people refuse to listen, preferring to use out of date pre-covid information. The bigger reason for setting a route "weeks in advance" is around hotel reservations. All main line trains in the UK are mass transit and are meant to be used at a moment's notice. Don't think Amtrak Trans- Continental, think more Amtrak North East Corridor or the better Commuter railroads in the US. You don't, or don't need to, book those in advance.
Just today I have been travelling on ludicrously cheap advance tickets I booked under 2 weeks ago. On the same route a fortnight ago I got the same daft cheap fares booked 3 days in advance-I wouldn't have got better if I had booked 8 or 12 weeks ago,