As a builder, we use Buildertrend for everything: file storage, selections, change orders, invoicing, POs, billing, budget tracking, schedule, bids/estimates, and as a communication platform to both clients and vendors/trade partners. We use the To-Dos, Daily Logs religiously.
But the plans and specs come from outside tools; Buildertrend is just the repository. Buildertrend feeds info to Quickbooks for issuing payments to vendors or tracking payments from clients, and our back office bookkeeping.
This system has worked well for us, our clients, and our vendors, across our whole portfolio of work from our smallest renovation project up to our largest (so far) $20mm build.
This may not be as helpful to a designer/architect, but considering design work feeds construction work, there isn't a downside to using a similar format to what the client is likely to see once they start construction.