If 100% of your devices are Hue and the automation it provides is enough, there really isn't a reason to switch.
But if you start adding a second brand like IKEA (their bulbs are a LOT cheaper than Philips) or Wifi stuff from Shelly, you either suffer the trap of 3+ separate apps or bite the Home Assistant bullet eventually.
I actually have both IKEA bulbs and Hue bulbs, but the appliance is different for both. I use the Hue bulbs where I want high quality lightning like the living room, kitchen, bathroom and office. I use the IKEA bulbs in places where I don't really care how good the lightning is; the hallways, toilet, garage etc. Automations for IKEA bulbs are in Home Assistant and for Hue they are in the Hue app.
IMO Home Assistant doesn't really do a good job with controlling the lights. It doesn't have the creative abilities to create or choose predefined "cool" scenes. Besides I don't want to know how much work I need to do in Home Assistant to re-configure the smart switches from Hue and their features.
In the end I can still control the Hue bulbs with Home Assistant if I want to. The Hue app doesn't prevent you from controlling the Hue bulbs from Home Assistant
The only fancy thing I need for my lights is what Apple calls "adaptive lighting", so that the colour temperature changes according to the time of day. The new IKEA Dirigera hub supports this too.
In the mornings and evenings all my lights are more yellow and bright white during the day.
The colour changing thing was cool for like 2 months, haven't touched it since (Except for my Hue Sync setup behind my TV)
But if you start adding a second brand like IKEA (their bulbs are a LOT cheaper than Philips) or Wifi stuff from Shelly, you either suffer the trap of 3+ separate apps or bite the Home Assistant bullet eventually.