Charging at a petrol station is definitely a bit crap, but on the flip side, its better than not charging and ending up on an AA lorry. I think in the ~5 years i've driven EV's i've charged at a petrol station two or three times, but in all cases it was critical because there was nothing else nearby. One time i rolled in with the battery showing literally 0%, having had a failed charge at another unit 10 miles down the road.
It feels like a stop-gap, however all of the big petrol providers seem to be looking at it, i guess they dont want to be left behind and want to get a foot in the door. It will certainly help EV adoption if you know that any of the many filling stations around also have charging. MFG has setup a few EV only sites, but they've also rolled out a lot of "hubs" with 6/8/12 chargers at existing petrol sites, which as an EV driver is far more useful than the usual effort of one or two units.
Charging is slow enough, without turning up and finding a queue for the one charger (or worse, its broken). So multiple unit sites are a huge draw for an EV owner.
Its very likely a huge profit source for their shop too, as if your sat there for 15-30mins charging the chances are your going to pop in for a coffee or a drink or whatever. Generally on a longer trip i will try to align the charging stop with natural breaks like lunch, so there will be some capturing of that market too.
Motorway services ofcourse are a different story, but the provision at most motorway services in the UK is utter garbage, so a lot of these charging hubs at normal petrol stations are popping up near motorways, to catch the folks who need to charge and want to avoid the motorway hubs as they're generally under-specified (often only 2 or 3 chargers) and massively busy.
As for the LPG side, its certainly a concern, availability has dropped significantly over the last few years. However i suspect its just never been that popular here in the UK unlike Europe, and with the move towards direct injection, it stopped being viable for new vehicles probably 10 years ago. Thus we're basically in a run-out period where its only used by older cars which are as time passes simply disappearing from the roads. Add in the EV side going the other way, and with limited space, as a business you can see its a very clear choice... Keep the large bulky LPG tanks for the 3 campervans and 4 V8 SUV's a day, with all the associated costs of maintenance and upkeep, to sell fuel with wafer thin margins... Or remove them, install some EV chargers where your making not only a bigger margin on the fuel itself, but you've got a nice captive audience for your shop.