I can see both sides of this.
On one hand, walking along the pontoon and onto the boat is hard to beat for convenience. Anti-foul and winter haul outs were not an issue for me on a dry stack, so this really did offer all the upsides of a marina berth and few downsides (cost aside, coming back into the dry-stack pontoons at 4pm on a summer Saturday would usually see boats rafted up or queuing afloat to await a free space alongside, which was a bit of a pain).
On the other hand, when I had Apache I always wanted to trailer her to the West Country for a long weekend's fishing but just never got round to it. Not having a tow vehicle for the last couple of years of ownership was a bit of a show-stopper for this to be fair, and I never really felt good about towing anyway, but this could have been solved by more experience towing. What I will say though is that I quickly got bored of beach launching off the trailer single-handedly. There was no pontoon to tie up alongside when I had her, so if I wanted a solo trip I would have to walk the anchor up the beach then stow the trailer and tractor before getting afloat. Just a chore at the best of times, let alone when I'm wondering if she had come adrift and was floating out of Langstone Harbour on a 6kt flood.
I'm considering a trailer boat for my next one (along with a vehicle to tow it) and maybe tow it down to Devon for the summer, then over-winter it back on my drive or maybe on a dry-stack on the S. coast for the cod season. Not sure yet, but given that I don't live 5 mins from a marina, I may as well get the benefit of being mobile and therefore more flexible in where I fish. If I have to drive 90 mins to the coast, then if I have a trailer boat I can pick and choose the direction I spend those 90 mins travelling in, rather than going to the same old ground chasing the same old dogfish.