Ask HN: What are the downsides of working for a consultancy?

I have an offer from a consultancy for projects in EU public sector. The salary increase is not bad and the title is a move up (I think). I'm getting to an architect role up from Senior Dev. WLB will be a bit worse though. I'm currently in a known product company in Telecoms sector.I'm in my 40s and have worked mostly as a SW dev up to now. The new role won't be hands-on as the roles I had so far (so I'd be very interested to read experiences from people that did a similar move).

Is that a good move professionally? Does it make sense? What are the downsides of moving from a regular product company to a consultancy? Would such a move increase my future prospects or narrow them? I need to be in business in some way or another for at least another 20 years.

No significant connections or network. I mean I won't be able to move to a high power/salary position to which this role would be a good stepping stone. Just me with my abilities have to be marketable for a good few years to come.

Thanks