My own experience of OT has been very positive. I got lots of help/ideas from the local council one.
When my council bungalow was being adapted I had help from the OT working from the housing dept. She suggested lots of things that I would never have thought of – including a number of things that I was sure that I didn’t need (eg a seat in the shower) but which have proved invaluable.
When money is involved – for disabled facilities grants for example the OTs hands may be tied and the advice may therefore be less useful.
Regarding a powerchair – in my area this assessment is done by wheelchair services and not OT. In my case I was allocated an indoor powerchair because I can’t self propel due to weakness and un-coordination of my left arm and I was experiencing a lot of falls. To get an indoor/outdoor chair you need to be not walking at all – using the indoor chair 100% of the time.