For a garage fun gun - it's ideal, a couple of easy pumps rather than one almighty nipple-clamping one...where you don't need or necessarily want huge power .
For the odd occasions where it's nice to have a bit more 'oomph' its available for a little extra effort and with a little tweaking its not difficult to get them nudging the UK limit.
Fancy an ultra carbine?.... Buy the Crosman shoulder stock for £20 and two minutes later... You've got one.
Fancy grips for not a lot - check.
All kinds of custom parts - check.
A lot of fun with no reliance on CO2, pumps or diver's bottles and access to every kind of spare or custom part you could ever want for under a ton....sure - if you want to sling loads of lead down range then pumpers are going to loose their shine, but for how many are out there you don't often see them for sale...which says something.