Just been having a chat to camping partner, we'll plan our week first and then decide to get one or not. It'd be around an extra £100 just for the cable and the weeks electric so a big difference if we don't use it.
Does give you the ability to have other mains electrical things
like fans and lights - and maybe cooking things or whatever!
True, but all my current camping kit is off the grid so gas, battery, solar etc. It might be a black hole of spending if I decide to go electric lol. I will say the idea of a fridge and electric stove sounds good especially as the new tent is quite large and designed for living like that. It is more money though.
If you are going for hookup, use it as you pay a fair bit for it.
We do both. I now have an Anker Solix for off grid - generally run the fridge off it during the day whilst the battery is topped up with solar.
We're at Bala in a tent for 5 nights and have gone with hookup - so fan heater (if it gets cold), and electric kettle and hot plate for cooking. You generally keep consumption under about 2kw to be safe from tripping, which your bike chargers will be well under.
Those look interesting, I imagine you can take it pre-charged as well. If we just wanted to charge cycling batteries, no other kit, I reckon investing in something like that would be best.