Well I have the OE Aerotec bow bag as supplied with a new one and I'm only keeping it for the sake of completeness on resale.
I had a new Honwave 3.5AE which was a boat show special offer with free bow bag... sold the bag on immediately.
All the bow bags I've had/seem hold the bag off the floor a few inches so if you put heavy stuff in them like an anchor it tries to escape the bottom by splitting the material... or it strains the zip opening... or strains the attachments to the tubes.
If you have to go bow-on to a crowded pontoon they are a pain to climb over.
In certain circumstances folks (particularly kids/teens) are well placed sitting on the floor at the bow and the bag prevents this.
I use a waterproofed heavy canvas bag for the anchor/chain/ropes/tow bridle which sits next to the fuel tank under the seat.... tied on just in case.
Everything else is distributed between two or three dry bags... not this make but similar...
Exped Folding Lightweight Waterproof Drybag Ideal for Canoe Kayak Sailing | eBay
They are waterproof and float even with a fair bit of gear in. They can be placed where needed according to the space around folks with you. I clip them on so they can't be thrown out.
In the ultimate worse case of abandon ship they can be quickly unclipped and taken with you into the water so you still have all your personal possessions. In the less serious situation of leaving the SIB on a pontoon while at lunch they are a neat way of taking the expensive bits like camera/phone/radio/gps etc with you.
One of the bags is marked "grab bag" in big letters and all aboard know it's the most important to take in a crisis with flares, backup gps, comms, water, torch, knife, sweets, 1st aid kit, car/house keys and so on
That's just how we do it... loads of variations with other folks and different needs.